GTX 460 requires two 6-pin PCIe connectors which you can find on a 500W unit. However, if you don't even game or use CUDA, you'll never stress the GPU to its full power, thus 500W is easily enough even with a heavy overclock (meaning high voltage) on the CPU. Is your CPU overclocked?
I'd recommend Seasonic S12II 520W, XFX 550W, or Antec Earthwatts 500W, HCG-520, Seasonic X-460/X-560, to name a few.