Ok. As most threads in this situation, there isn't much point upgrading to haswell. Although there may be some performance increase, IMO, the difference is not worth it and can be minimal. The 2500k is a great overclocked, what are you running it at, what board and cooler do you have?
My recommendation would be to get a nice overclock, 4.5 ish, and wait for the new AMD cards to come out in around 2/3 days.