Jordan, from what I have read and researched, seems like a great card that gives the best bang for your buck it the Nvidia GTX 650 Ti Boost. On a ton of bench mark sites it held up quite nicely with cards almost twice and much and beyond. Based on some of the other hardware you have, I don't think you would need to go any further. However you wouldn't be able to do SLI (multiple graphics cards together) unless the motherboard supports the nforce chip set. Porbably not a big deal for the scope of work you would be doing. Hope it helps!
You have not stated whether you are going to replace your current HD 7600 or try to run both the new card and the old one. I am not sure that your power supply would handle if you went with a GTX 650 Ti (134 watts).
The suggestion above from cc_merchant for the GT 640 (the GDDR5 memory version with 1 GB of RAM) is only 49 watt max, but it is a weakling but probably a fair match for your AMD processor and only 8 GB of RAM. A compromise might be the plain GTX 650