I managed to utterly miss this one, although I actually picked up the point anyway. Take it from me, a big pretty number on the side of the box doesn't mean much when your processor will hold you back, which is what you originally asked. You then received several responses saying as much and offering good advice that would be to greater overall benefit, and chose to freak out on the people giving it. If your reason for not upgrading the processor is tech knowledge based as opposed to being completely thick and incapable of comprehending that the 460 is more than sufficient in your system, you should probably say as much.
And odds are good you can find a local shop that can install the processor for you, likely free with the actual purchase of said processor. The 1GB superclock 460 and the quad core would, at the same cost as a 480, give you a larger overall performance increase.
If you don't believe me, research it yourself.