Dell Inspiron 530... can i update it with a nvidia video card?

I need some really specific answers into helping me get a new video card.
I own a dell inspiron 530 with duo core quad processor.
what i really need to specify in what i need help in is a new video card and power supply:
What new video card, the best.. even tho it's expensive. please name me 3 of the top-line, video card I can upgrade it for the dell inspiron 530:
I would prefer nvidia
pci 2?
pci express?
nividia sli?
256, 128, 512 mb or 1gb?
I would prefer tigerdirect.com to link me some of the video cards.. if not.. newegg.com is ok
and when getting a new video card..
what power supply can i get that will support the new video cards.. and would it fit into the dell???
I appreciate your help