without knowing what motherboard your computer has, nobody here can actually say whether or not that card will work in it, but it's definitely got enough oomph for the game.
Heh. I wouldn't get a 7300GS if I were you. If you ONLY have budget of $100... go for something along the lines of a 6600 or 6800. The 7300GS is an underpowered POS...
The 7300 would probably be a bit better. Do not get a 6600, those cards are both better. The 6800 however beats both. Going to a retail store will cost you more. Try www.NewEgg.com they are a lot cheaper.