You can pretty much use any of these lipo's that fit your car mate as long as they are 7.4v (2 cell).
http://www.hobbycity.com/hobbycity/s...2&ParentCat=85
They are dirt cheap and great quality, very punchy. Anything from 800mah and up will last more than a 5minute race so depending on your motor/gearing/driving you should get 2 races out of a 1750mah. Also, the more mah you buy the quicker you can charge it and the less topping up you are doing which means it increases pack life.