I use mostly use the sports mode. It seems to be in focus just not quick enough.
dccarver, your setup it is not the most adequate for sports photography. It only means that with your setup, the percentage of great photos will be lower compared to better setups, but you can still get great photos ! Pro sports photographers can't afford to miss the moment, so they use expensive equipment to have a higher percentage of successful photos. In your case, you don't need to have such a high percentage of successful photos. Also, I am assuming your daughter is slower than a pro athlete, and this helps your AF and also the ability of freezing the moment.
The first question is this, are you taking the photos outdoor during daytime with adequate light ?
If yes, then you should not have any problem in taking good photos.
Don't use the sports mode but switch to AV, and set the lens wide open. Then step up manually the ISO until you get a shutter speed of at least 1/500. Personally I try to use at least 1/1000 for rugby, most of the time reaching even 1/2500, but these are faster athletes. You need to have a compromise between ISO and shutter speed. Use Servo focusing with center point only, and set continuous shooting so that you can shoot like a madman
. You can always place the subject away from the center with a better framing later on with cropping. Aim the subject on the center point and focus continuously, even if not taking photos, so that the camera can fix the focus while the subject is moving. I like to use back button focusing : http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=2286
Having said that, if you still want to upgrade camera, I will go for the 7D. Neither the 60D or 7D will give you a better freezing ability, since their ISO ability is similar to your 550D. Also, neither of them will give you a better cropping ability.
But, the 7D has a better AF and better FPS, which gives you a better percentage of successful sport photos.
For better freezing ability, you should get a faster lens, such as a 70-200 2.8. It also blurs the background better, has faster AF, sharper and has a constant aperture which is good for sports.
I suggest to practice with what you have first, so that you get a better idea of your needs.