I suggest swapping CPU from X4 640 to X3 455 and from GTX 460 to 6870. You can unlock the 4th core of CPU if in case u need more from it.
Also you need to specify which resolution r u gonna be running and wats ur total budget for this build and location?
Well I usually play at 1600x900 and my budget was like $400...
It's a huge upgrade from my previous system
CPU: Intel Pentium 4 2.8ghz
GPU: XFX 9500GT 1gb
PSU: 350 watt
OS: windows 7