No worries, but like the other member mentioned, if you still have your 2500k, you can try pushing for 4.8ghz, my old 2500k did 4.8ghz with I think 1.41v I think? Been a while. If you have a z77 motherboard, you can go with ivy and save on the mobo expense. I know I like upgrading cpu's periodicly just for the oc fun. Keep in mind though if you do go amd, for gaming the FX 8xxx series seems to be on par with the 3570k/4670k, and the advantage in having a 3770k/4770k for gaming is small unless you have one of those games that can use it (think Arma is one of them).
Keep in mind this is a loose estimate, I have owned both a 2500k and 3570k but not the 4670k, seems like the estimate would be close on the 4670k that I mention below from reviews but I can say the 2500k and 3570k in my system proved to be what I listed below.
3570k at say 4.5ghz = 2500k at 4.65-4.7ghz
3570k at 4.5ghz = 4670k at 4.3ghz
2500k 4.8ghz = 4670k 4.4ghz
Keep in mind the real world use advantage in going from a 2500k to a 4670k would be small but I do know how fun it is to overclock a new cpu
There is also supposed to be a new haswell stepping to come out this year with better thermal paste used and some other small changes. I havent heard much recently though.