I'd say all Phenom II X4 or X6 could use up to around a 1050 Ti. The problem I'd have suggesting that card is compatibility. That old bios in the motherboard might not work well with the new cards.
If that was my computer I'd look for something like an HD 7970 or. less powerful, an HD 7870. Also, the later cards that used similar tech, like the R9 280 and R9 380 cards. The only downside there is you'll need a better power supply than for the new cards.
I have no idea what games you play, what resolution you run, or what kind of power supply you have, so my suggestions take none of those important elements into consideration.