My 2p
I'm waiting for Skylake. My system is same generation as yours (same mobo family) but with a better CPU (Q9550 @ 3.6ghz) and GPU (3Gb 7950) than you, but runs Skyrim, Elite Dangerous, Arena Commander, Rome II very well at 1900x1200.
My kids system (my cast offs) is a C2D8400 and a 5850 and he is runnning Elite Dangerous at 1680x1050 no problems.
So having waited this long to move to i5/i7, I don't want to buy into old architecture, so I'm waiting for Skylake and DDR4.
I think your best bet is cheap CPU upgrade (Q9xxx) now, save for a better GPU that will last into your next platform upgrade and don't spend money on Broadwell/DDR3.
if I knew Skylake would work on an LGA1150/DDR4 board, I would have been tempted to buy an i5 now, but as its a whole new platform, I've decided to wait.