I you are like me you have a proper self-built machine.
I have a q6600 with a 400mhz (1600mhz) fsb and the processor is running at 3.4ghz completely stable. I could do 3.6ghz but it runs too hot and is not 100% stable.
Sure its not a core i5 but the performance is only off by 15% or so to a non-overclocked chip.
The biggest performance limiter in games is NOT the processor but your video card.
I would switch to a Radeon 7770, 7850, or 7870 and that should give you some more boost for playing games and extend the life of your machine for another year or two while you save your pennies. (Assuming your powersupply is big enough...)
Next time you get a desktop machine get one with 100% standard parts. Newegg and Tigerdirect both have system assembly services.
Techreport.com and other websites have system build guides that they put out every season. When you have about $1k go buy yourself a far better machine.