You have zero need to buy a new processor.. 2500K is not a bottleneck at all.. and the CPU's for only gaming are side grades if anything especially vs your CPU overclocked.
I think this is the best advice. I have a 2500k and play GTA 5, CIV VI, Dawn of War 3 all at above 60fps at 1080p. I would love to upgrade, but just no real need. What are you playing that you feel like you need to upgrade? How much RAM do you have and what is your GPU?