x32 and x64 are complelety different. ( in OS terms)
if you want x64 windows you will have to do a complete NEW install. dw windows takes your old windows file and stores it as window.old so you will still have documents and downloads.
no replacement parts are needed. though i recommend you have your wireless driver for x64 on a flash drive or cd so you can have internet to download the updates you will need to make x64 work at its best.