Can I upgrade my HP Pavilion Slimline s5110t?

I just bought modern warfare 2 and i need a good graphics card. My operating system is Windows Vista 64-bit 2.5ghz 4GB RAM and dual core. Can I put a Galaxy-NVIDIA GT220 1GB DDR2 in my computer to play modern warfare 2?|||Because it is a "Slimline", you will need to find a low profile video card - not a full size card. Also check to see if your power supply wattage is sufficient to run the video card.