I currently have a ATI 512 128bit 4670. Pentium 4 3.0 GHz/2M/800 (I have a Intel Pentium D 945 3.4GHZ/4M/800 SL9QQ in my closet I might put on, tell me if that would make a difference if I install it.) The PSU I have is this 400 Watt made by Corsair this link is at the bottom of this post. I usually get low frames when playing WoW in intense areas (Like Raids and Battle grounds, can be up to 40 players playing). Would putting in that CPU help alone without getting a new graphics card. I was thinking that the 5770 ATI is the best card, but I am not too sure and that or the best brand. I am open to any suggestions. I am using a Dell Dimension e510. The Main question is, what is the best graphics card for my PSU. I can worry about the PSU and my system later.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139008&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-RSSDailyDeals-_-na-_-na&AID=10521304&PID=3463938&SID=ef8xsxe86j
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139008&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-RSSDailyDeals-_-na-_-na&AID=10521304&PID=3463938&SID=ef8xsxe86j