Looking to upgrade my aged HP m7360n. I am already planning on putting another Gig of RAM in it. So my question is what is the best GPU for the stock 300w PSU? It is 19a on 12v (if memory serves)I really don't want to buy a new PSU. Since I am building a gaming PC in 5 months. So any suggestions? I was thinking 8400gt 512mb PCIe. I just want to make sure the card will run with that PSU.