I fixed your replies. Try to keep them all in one post like I did.
So you have two issues for playing the newest games. First, you have a quad core/thread CPU. Newest game engines prefer being able to tackle 8 threads at a time and suggest the 3770K for this. Second issue is the stock clock CPU. The 2500 is very similar to the 4690 if you can clock it high enough. There wasn't that much improvement between the two chips, the 4690 is just clocked faster. I'm not sure what your issue is with OCing it. You'd have to start a new thread on that.
Based on this new information, 4k with stock clock 2500, I'm not sure I'd bother upgrading. It seems you either need to figure out how to get another GHz+ out of your current CPU, or just upgrade to something newer.