Defiantly go for a new GPU. I would suggest, if you arent willing to shell out a lot of money, the GTX 760. Either the Asus DirectCU 2GB GTX760 or the EVGA SC GTX760. Both are great cards but the EVGA comes with slightly higher clock speeds. They go for about 200$ but you can probably find one for cheaper right now. 600 watt is fine for running a 760. With my current rig, a Asus 760, FX-6300 OC @ 4.3Ghz, 8GB RAM, 7200RPM 1TB HDD, I get about 40-55FPS @ 1080p with LCPDFR, CRYEnb v3, ELS V8 police car pack and about 7-10 other mods such as trafficflow, braveheart, etc on Max-high settings.