If you upgrade your motherboard to a Z75 or Z77 you can overclock your 3470 using the turbo multiplier. That is an option.
You can also upgrade your graphics to a 7950. They are costing about $300. I would go for the gigabyte model since I like its cooler.
Your CPU is plenty strong right now. If you did want to upgrade that, I would go for a E3 1230v2 and overlcock that with the turbo mulitplier. Better than getting a 3770.
I would suggest grabbing the motherboard or CPU now. Haswell will not be a major game changer so no sense in waiting for that. Then after the next gen of GPU's hit, maybe grab one of those or a 7970/680 when they drop in price.
Selling off your 3470 and old board and gpu will offset a lot of the cost allow you to buy a better PSU as well.
Unfortunately, your main limiting factor is the 7770 right now. You could grab a 7870/7950 and grab another to crossfire with when prices drop.