First YES you can overclock the cpu and the motherboard supports this....if not with stock bios maybe with an updated bios version?
Read this then look at the url below for the explanation
If you don’t buy a K-series chip and instead grab a Core i7-2600, Core i5-2500, -2400, or -2300 (along with a P67-based motherboard), you’ll still have access to “limited unlocking.” This basically means you can set clock rates up to four speed bins above the highest Turbo Boost frequency setting available at any given level of processor activity.
So, take a Core i7-2600 as an example. The chip’s base clock is 3.3 GHz. With four cores active, it gets one bin worth of additional performance—3.4 GHz. Four bins above that would be 3.8 GHz. With two cores active, Turbo Boost bumps it up two bins, to 3.5 GHz. Limited overclocking makes 3.9 GHz available in that case. In a best-case scenario, only one core is active. Turbo Boost adds four bins of frequency, yielding 3.7 GHz, and Intel’s overclocking scheme lets you run at up to 4.1 GHz.
This is on Tomshardware
http://www.tomshardware.com/reviews/sandy-bridge-core-i7-2600k-core-i5-2500k,2833-9.html
this should give you an idea of what and how much for both!
Good Luck
Respectfully,
tekman42