Canon Lens Recommendation

[aich75013]

I was looking for help if I should look into a new lens.
I mostly shoot sports (my daughter's soccer team).
The lens I currently use is a Canon EF 75-300mm f/4-5.6 III Telephoto Zoom Lens. It was an extra $99 when I bought my camera.
The camera is a Canon XSi.

I have some pictures on my webpage for an idea of what my current photos look like, but I don't know how to point to a direct link.
http://www.theayalas.org/albums/
You can navigate on the left to 2010 --> Babcats Soccer

I was looking at these two lenses:
http://www.amazon.com/Canon-70-200mm.../ref=pd_cp_p_1
http://www.amazon.com/Canon-70-300mm...9974109&sr=1-1

I was looking for opinions on the 2 lenses (or others) or if I should stick to what I have now. The 70-200 seems like a nicer lens, but doesn't have the same range.
One thing I don't like about mine is the slow AF. It is not USM and does not have IS.

Thanks.