Looks like the only thing bottle necked on your PC is the video card and check your power supply to see if its big enough for a bigger video card. I would try the XFX Double D Radeon HD 7970 or the EVGA SuperClocked+ GeForce GTX 680 if NVIDEA is your preferance . I don't know your price range, I could suggest a different card based on that.
And when you said your budget is $1000 - does that mean just for upgrades? If that's the case - a GTX 690 might be more your style if you are truly serious about your gaming ( however, that will definitely require that PSU upgrade )
"We apologize for the inconvenience, but the item you are looking for has been deactivated. Here are some similar products that you may wish to consider"
The guys here try to convince you to get a new PSU, because what a 80+ certified means is: (wiki) is a voluntary certification program intended to promote efficient energy use in computer power supply units (PSUs) if it's not 80% it might run on lower power, your pc is not getting enough power, things can't run optimally.
THAT AND: a PSU loses power every year you use it, I'm not an expert, just enthousiast trying to help you, but due to capacitor leakage or something, your wattage reduces over time.
And yes a 480 might run slow on a 2600 (more than fine) machine.
If it is, it only has 1 6pin PCIe connector, which isn't enough to run a high end card (like the 680 or 7970). I would upgrade anyways, just because it is lower end as it stands, but you cannot use a high end graphics card without upgrading your power supply. The current one physically doesn't have enough plugs.
I hope you enjoy your new computer. It will be a beast.