Need help with PSU and Graphics Card!!?

You will not have any problems with the card. Geforce 9500 is a good card to play the games you mentioned. I am playing Modern Warfare 2 on 8400GS and it runs quite well. You need to get more RAM to play these games, atleast 2 gb. You have a P4 single core processor. But most games require dual core cpu. The game "Operation Flashpoint Dragon Rising" even needs a quad core processor for smooth play.