From what I can tell your PC has a 250W power supply, way below the minimum. If that is the case, your PC wont even comfortably support a low end card. If you are going to upgrade your graphics card, you are going to have to also upgrade your power supply. And yes, your processor will no doubt bottle neck a GTX 560. You will need a lower end card or an upgrade to your entire PC in order to support a GTX 560.