Hd 7750 would be good.but for higher card he need new psu.by the way hd 7750 > gtx 650 with latest drivers.
Thanks for the info. I'm not going to be playing Battlefield 3 on here! :P Sometime in the future I'll probably upgrade the PSU and get a better card. This is just a quick upgrade.
EDIT: There is a 2 GB DDR3 and a 1 GB GDDR5 I believe. The latter, right?