Really? He would need 4 identical 2GB stick sof DDR2, either PC6400 or PC8500, which even second hand may well cost more than 8GB of 2400MHz DDR3.
I myself would rather save that expense, because a G3258 with an H81 motherboard and 8GB of DDR3 will play many games and run plenty of applications better than the old Q6600 LGA775 system with DDR2.
Investing in a G3258, with a Z97, and 8GB of DDR3 is now what I feel the OP should be considering, but that will be after he states his current PC monitor and case.
Another option could be an LGA775 compatable all in one CPU cooler. It could help overclock that Q6600.
An all in one cooler that is compatible with 775 and 1150 is certainly on the list. From my thread in the watercooling section it appears that the raijintek triton fits the bill nicely.
I'm currently using an old 17" tft monitor so it ain't great and I think that's where my next purchase lies. Pretty gutted I missed out on the Asus panel @149. They are now out of stock.
I'm not throwing anymore money at ddr2 so 4gb will have to do!