I'm looking to upgrade a pre-built HP Z220. It has 8 gigs of ram and an i7 3770 processor, but the graphics are very lacking. In addition to that, the power supply is also very small. I'm accustomed to building systems with a large tower, and this has a very small case, not the typical width of a larger tower. What power supplies and graphics cards are available for such small cases? Target budget is ~$200, any recommendations would be greatly appreciated!