Graphics card that is compatabile with Insperon 530s?

My friend is looking for card that is compatible with his dell that he is getting that has a Insperon 530s and preferably one that is $50-$100 dollars any help would be appreciated.

within that price range, i'd maybe go for something like the GeForce 9600GT. or if he can stretch it a bit further, a 9800GT.

i'd say 4670 cause im pretty sure that has a weak psu.