This is my first upgrading project, taking my nearly 5 year old PC and adding a new video card, 500W psu, and 2Gbs of memory (that will come later). I love really think I made the right choice on the video card but the power supply is the one in question. My first choice was a 30 dollar Hec Compucase for 30 bucks but I went against fearing it was too cheap. Then I picked out a nice Rosewill one for 50 bucks but sadly it was sold out this morning. So I picked middle of the ground, and got a Apevia 500W PSU for 40 bucks with free shipping. The reviews were very middle of the road but with a lot of reviews on Newegg, you have to take them with a grain of salt. My budget won't permit me to go higher than 50 bucks because I want to save money for my first build. I know about the price of quality but I want to extend the life my media center PC for a few more years. Anyway, here is the link
If you already purchased a video card and a power supply, then what is your question?
A single 4650 video only uses about 90 watts at full load. Amperage should be pretty low too. The 4650 is not a power hungry video card.
The Corsair 400 watt power supply mentioned by Knotknut has a +12volt rail rated at 30 amps. That is more than enough to power your system and it comes with a 5 year warranty.
I'm just feeling Buyer's Remorse for the PSU after all these bad things I hear about it from the reviews but I read the same about it before and decided to get it anyway. I guess after I paid for it, the bad reviews carried more weight and I got scared.
I normally don't get this way when I buy stuff. It just when it is my first upgrade project, I got frightened.