^^ Okay Sir first off is that a standard cheap SMPS that you've powering the RIG, if yes please change it with a
FSP Saga II 400W ~ 1900/-,
then for what purpose would you like to have the graphics card. If it is gaming you'll need to up the SMPS to a
Seasonic S12II 430W ~ 3000/- and the card to watch for will be the, AMD HD 6670 ~ 5500/- OR AMD HD 5770 ~ 6500/- [if you want the card to soldier for another 3-4 years, though in both cases your CPU will be a major bottleneck while gaming].
Else if it is for HTPC and HD-content decoding with light gaming, grab the HD 6670 ~ 5500/-.