What can I do to upgrade/cut costs from this PC?

are you opposed to ordering tomorrow and what's your budget? some good deals online for parts that you could really boost that system up, because in honest, with that CPU and GPU, your not going to be gaming at very high settings on newer games, etc.

That cooler isn't going to do much better than stock. Either go Evo212 or better or don't bother dumping $20 on it.

Don't worry about the thermal paste, $5 waste for next to no difference on a stock cooler.