corsair VX 450w

i'm going to buy a corsair VX 450w for my new 8800gt 512mb. i'm wondering if the PSU is powerful enough and whether i need another PCIe adaptor. I've been told that the corsair i'm buying only has one adaptor in box. I think the 8800gt needs two PCIe adaptors to function, and if i have to buy a more powerful/expensive PSU, i will probably buy the 8800gts 320mb. I have an HP a6130n that is in stock condition which people say is running w/ a 250w PSU.