Just to check that's not a typo, you've got the i5-2500 (not the i5-2500K)? If it's the non-K that you have, then it's not overclockable to any large extent. You can vary the BLCK on your motherboard, but not by very much so your OC will be correspondingly small.
Your motherboard is good though, and should have plenty of OC features. What you could do is sell the i5-2500 and buy the i5-2500K; the extra you'd have to stump up to cover that would be relatively low if you get a good sale for your existing CPU.