Graphics card:
Sapphire Radeon HD 4650 1GB GDDR2
http://www.newegg.com/Product/Produc...82E16814102843
$54.99
Power supply:
Corsair VX550W
http://www.newegg.com/Product/Produc...82E16817139004
$89.99 - $30 MIR = $59.99
I'm going to have to do some research to figure out what RAM is compatible with your board. I will say that you SHOULD wait a bit longer, save up some money, and get a new machine. The Pentium D isn't quite completely obsolete yet, but it's edging closer every day. By next year it may not be able to play most new games. I would save up $650 and get a mid-range gaming machine, it's a better return on investment.