I have a HP P6720f. It has a Bestec 250watt power supply. I think it has 14amps all total. I have 10 GB of ram in the computer so far. The computer has Integrated graphics using ATI Radeon 4200. I would like to upgrade it to something a little bit better. I have 2 hard drives installed in the computer already. I really dont want to change out the Power supply. Looking to spend $50.00 or less on a new graphics card. The main games I play is Sim city and lord of the rings online. So what would be a good graphics card to put inside the computer? It uses a PCI 16 slot.