Originally Posted by Revs
That's odd. In the UK both 7 and Vista came with both versions in the box. Having the retail version you should just be able to get the x64 version on a torrent or something and use your current key.
Regarding a torrent I don't know where to look, as it seems to me that they are legal if you download them and you have a purchased key, but I'm sure people download them and apply cracked keys as well. There's a lot of grey area...
Where is a safe place to get a torrent for this which I could apply my legit Vista Home Premium key to? If it's safe, I wouldn't mind saving $15.