amd hd7770. should be able to find one of them for under $100. Should run it nicely on high settings. note that if you want to run the high res texture pack on it, more than 1gb vram is needed to run it smoothly.
Thanks for the product, but do you think the hd 7770 would be better then this one? EVGA NVIDIA GeForce GTS 450 1 GB GDDR5