You have copied a lot of totally useless information. What we really need is just the motherboard/CPU/graphics card ETC.
Mobo: Asus P5Q-PRO Which I see is quite old as it is a socket 775 motherboard.
CPU: Intel Core 2 Duo 64 again old tech.
Graphics card: NVIDIA GeForce GTX 260 that unfortunately will not handle todays games on anything but low settings if at all.
To be absolutely honest there is little point in upgrading as the money you would spend would not be worth the minimal improvement.
Do you have a budget at all? It might be possible to cannibalise your current PC but buy a new motherboard/CPU/GPU and RAM whilst using the hard-drive perhaps PSU but as you have not specified the wattage that might not be possible.