Welcome Raziel,
Your mobo is very unlikely to support the core 2 duo processors. This would mean an upgrade and i would suggest a Gigabyte P35-DS3R mobo (i have one and im very happy with it) and either a Q6600 or for a cheaper option an E6700. I wouldnt bother with the QX6700, its hefty premium is not worth the unlocked multiplier and the speed (which can easily be achieved by an oc'ed q6600).
Also, wait till july 22nd for a price drop on intel processors.