May I ask what kind of photography you are interested in pursuing? Are you interested in doing more and more weddings in order to earn income, or is the income from this work just an added bonus which will allow you to buy more gear in order to pursue other photographic interests?
I ask, because when you are first starting out and interested in generating income, the best thing to do will be to rent the lenses you need, rather than buy them. This will keep you in the black. It takes a $2000 lens some time to pay for itself when you're just starting out. It's good to own some nice lenses that you like and are comfortable with, for sure, but it's not something you have to do all at once. You can do it gradually. There's no reason to put financial pressure on yourself at this stage in the game if you're not sure about what you want yet. Buy the lenses you love and will use a lot (even outside of doing wedding jobs) and rent the others. Renting will give you the opportunity to use anything you want.
The 17-40 is great, I'd keep that one, but if you only own body, and are shooting weddings solo, you need that mid-range zoom (24-105). As I'm sure you've experienced, things move very quickly and weddings and you may find yourself in situations where you need more reach than the 17-40mm offers, yet you don't have enough time to switch lenses.
There is no doubt that you need a longer telephoto however, I will not advise you to sell the 24-105mm at this time in order to buy it...not unless you get a 2nd body so that you can have something wide at the ready (without changing lenses).
You could shoot an entire wedding with a 24-105mm on a single body, and still get pretty good results if you *had* to...and it wouldn't be that bad. That's the value of a mid-range zoom like the 24-105mm.
You could maybe do it with a 17-40 only, but portraits would not be a pretty sight. And you'd miss a lot with a 70-200mm only. On paper, it sounds good to have a 17-40, a 50, and 70-200mm -- that really covers every length...but it doesn't cover them in an ideal way with just one body--it will actually be an incredibly non-ideal setup and a pain in the butt to use. You'll be switching lenses way, way, way too much, and missing shots, slowing down the pace of the wedding, and it will be hard for you to get into a good rhythm of shooting.
The appeal of the 35/1.4 is understandable, and I won't try to dissuade you on that. Just keep in mind that your lens bag is getting pretty large, and if you're just on one body...it's going to be tricky to make use of all the lenses you bring with you. The only way to know for sure, however, is to try it out -- you might love the lens, or you might hate it. Try it before you buy it.
Keep the 24-105mm, it's a solid performer. It's great for outdoor weddings. Try a 35mm f/1.4...if you like it, consider buying it. The 35/1.4 will be great during receptions, certain kinds of detail shots, etc.
You still need something to cover your tele needs. If it turns out you aren't crazy about the 35 after trying it, then buy whatever 70-200mm is in your budget and you're done. Don't worry about mkI vs mkII vs IS, etc., just get what you can afford. IS is not that important for wedding work--fast shutter speeds are, and every version of the 70-200mm f/2.8 L lens that Canon has produced has been more than *great.* I use the old 80-200mm f/2.8 L "magic drainpipe" professionally, at weddings, constantly, it's my favorite lens of all time...and I've had it since I got my EOS-1 film camera in the early 90s.
However, if you love the 35mm, and use some of your budget on it, then consider the 200mm f/2.8 L prime along with it instead of the tele zoom.
You could probably get both the 35mm & 200mm for close to $1500 if you buy used (not much more new - sell that 85mm and you're good).
You won't have zoom with the 200mm prime, but it's fast, super duper sharp, inexpensive, and most of the time, with 70-200mm lenses, you're either on 70, 135, or 200. The 24-105 covers the wider end of that range already. Just break out the 200mm when you know you are going to go around and take tele shots.
Then you've got your bases pretty well covered -- two fast primes for low-light indoors (35 & 50), a good wide (17-40), good moderate-tele zoom (24-105) that will work great outdoors, (and indoors with flash), and then a brilliant, fast telephoto. That's more lenses than any single photographer really needs for a solo shooting job. You'll be hard pressed to have the time to use them all if you only have one body.
It's a misconception to think that you need to cover every conceivable focal length--it really isn't true, you'll be plenty close enough for a while if you go this route. Not having every possible focal length also forces you to try different things w/regards to composition.
To reiterate (1): You've gotta have a mid-range zoom if you're going to do weddings solo -- if you sell the 24-105, I'd only replace it with something like the 24-70mm -- but you don't necessarily have to get the mkII, you could get a used mkI, or even one of the older 28-70mm f/2.8 Ls.
Notes (2): If you're going to keep doing weddings (I'm just assuming solo,) you need a 2nd body more than you need to buy another lens. Beyond a 2nd body, you need a telephoto more than a 35.
Bottom line, rent things before you buy them -- rent some things you haven't mentioned too -- you might fall in love with one of them -- then buy what you can see yourself using long term -- and you don't have to buy the latest and greatest just to be in the game, Canon has made lots of good L lenses over the years, they are mostly all good, some of them are quite cheap now, and great wedding photography is about skill more than which version of which L lens was used. Find out what you like and works best for you.
Attached a couple of 80-200mm f/2.8 L "Magic Drainpipe" shots here, these are just a couple from the last year that I like, both 80-200mm shots were taken on the 7D.
