Which shows that it isn't that far behind. I think it's a bad investment to ditch the 4770k. I'm sure a lot of people would like you to sell your hardware. Like others have said, skt1366 parts are getting scarce. In all honesty, I don't think you're going to see much of a difference as far as real world performance is concerned. I would stick with what you have unless it is slowing down, which I seriously doubt. Haswell is newer tech and benchmarks might show it to be faster, sometimes, but in most real world cases. I don't see it being more than a few frames per second on average.
End all: Don't waste your money and hardware. Just get some more ram for your current rig if you need it, otherwise my recommendation would be to leave it alone. Now if something is going slow already, that's another story but you'll lose performance if you're doing anything that can utilize all 6 cores (12 threads). There is a famous saying, "If it's not broken, don't fix it." In this case it's more of, "If it's doing what you need now, anything newer will do the same thing just as well."
So leave it alone and enjoy your 4770k.