The new CPU will not provide a massive leap in performance. Also, your video card is an entry level model and really is not a gaming card.
You would be better off saving your money and upgrading your entire system. If that isn't an option, getting a stronger video card would help with gaming in most cases more than moving to that CPU.
So, what is your budget? What games do you intend to play? And, what resolution (i.e. 1920x1080) do you plan to game at?
im not trying to run anything to fancy like cod, just trying to run games more smothly ( i can run darksiders ) but its a bit slow... im just wodering if changing my cpu will enhance the performance of the fps + i also enjoy playing css but everyday it keep on geting slower, use to get over 150 fps during the frame test now i get under 80-90 fps) and system requirements lab says its not my video card its my cpu stopping me from running these games smoothly