For $200 you might as well keep your money.
There is not a card on the market in the $200 segment to "upgrade" to.
The best you can expect is a 10% to 15% better performance in some games, not all.
The bottleneck in your system is the processor. It is holding the 460 back.
A processor upgrade would give you the same upgrade as a new video card.
The 560 is two tiers above the 460. it is basically an overclocked 460.
But it would also be held back by your processor. so you would not really see an improvement by buying it.http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-7.html