I LOL`d so hard at that, 1.8ghz CPU . . . .i mean come on, what do u think needs to be replaced ffs. Also why would u put a GTX460 into a machine with a CPU that would bottleneck €50 graphics card. Pull out the GPU and build a new PC using only the 460 from your current rig.
Im using a gtx460 on stock not an OC edition and i am getting 80<>99 FPS, drops to 50 for a couple of seconds in space dock, all settings maxed. GTX460 is more then enough for the game, u need more CPU then GPU with this game.