Really you want to be looking to move to at least a Sandybridge series i3/i5/i7 to keep up with that 760 or an AMD 4300/6300/8300 series. But this would require a new motherboard and RAM.
You could, if your motherboard will allow upgrade to say a Q6600 + quad core and you could probably run that with say a 500 series nVidia card and that would play most stuff up to say 2012 at high settings and should provide playable FPS on recent stuff at low/medium settings.
What motherboard do you currently have, what's your budget?