JGroth, I fully understand your low budget issues. Actually, one of the reasons I started to study PC's was to find ways to be able to play games on the mediocre computer I could afford. Even my current rig is a low budget one, just a year newer than yours. I've paid about 350 for it, partially paying the upgrades by selling the weaker parts.
If by 750 you mean an Nvidia GTX750, that's a good start. Not stellar but playable with the settings all down.
The FirePro V4900 really falls way, way below minimum requirements no matter what your OS is. By benchmarks it scores roughly similar to the integrated one you're using now, or worse. A GTX750 scores over triple of those.
As a reminder, on Nvidia cards the hundreds tell the generation and the tens the power. GTX #50 are entry level gamers and basically the next generation #50 is on par with the previous #60. Same goes for higher tens. Thus a 1050 equals a 960 which equals 770 (800 series were for laptops only and were based on the 700's). Note that the "higher tens" cards require a power cable from your power supply!
