What PSU and Graphics should I get? Any good one on Amazon.co.uk?

I want to upgrade my http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=6269812&csid=_21 I'm looking for a new high watt psu which can support all the things in my computer but I also want to upgrade my graphics card so any suggestion there would be good. Any good one on Amazon?