you dont have enough money to get that and a good enough PSU dude. trust me, you DONT want a crappy PSU. ive even seen crappy PSU's blow up video cards\motherboards.
i know you, all you need is a 8600GTS, and a rock solid PSU. when you play games do you bump up the settings to high? i highly doubt that, therefore you dont play games on there max settings, so you dont neeed that kind of horsepower.
also, make sure your parents get you that ram\cpu combo before you use ALL your money on that video card