Hi, I'm a complete noob with computer parts, and want to be sure that I don't buy the wrong things. That said, I'm looking to add a graphics card to my Asus Cm1630 desktop pc, and I'm unsure of what type I need. I've gathered that I need to upgrade my power supply as well, to something with a minimum of 550 watts, but again, there are many different types, and I don't want to buy the wrong ones. Help would be greatly appreciated, this upgrade is Looong overdue.