So a new CPU is better than a new graphics card ?
That depends, if you have a video card around the gen of Nvidia 8800 or better or an ATI HD3000-4000 series or better (with more than 512mb VRAM) and a CPU with less than 2.6GHz (talking about dualcore in this case, stock speed), you're indeed better off getting a new CPU than a new GPU for this kind of games.