First of all, i really like your pictures, the long exposures in particular.
To be honest, when i first started with my first dslr (550D/T2i + 18-55 IS II) i loathed the kit lens too, but then i realized it takes serious money to get something better. I would say stick to it. It's good enough if you use it at narrow apertures (f/5.6 and smaller). I wouldn't recommend the 28-135 either, because 28mm can be too tight on an apsc sensor (if you wonder what the difference between aps-c and full frame is, check here
). My first lens after the kit was the 50/1.8 from canon; for the money, nothing beats it: it's got good sharpness and a quite large aperture. Keep in mind that its autofocus system, while reasonably accurate, is slow and noisy. Some months ago Yongnuo launched a knock off of this lens that sells for barely 2/3 of the price of the canon. The reviews seems good, you might consider it. If you really have an itch for a new toy, i would consider either a Canon 10-18, a brand new ultrawide zoom with good quality and reasonable price, or, if you are into portraits, a couple of flash with remote triggers and light modifiers. Sorry for the long post, i hope it'll help you make your mind!