Vista Upgrade 32-bit/64-bit compatibility issue

Right, so I purchased the Vista Ultimate SP1 upgrade package via the It's Not Cheating deal, and now I'm left with three files, and wondering what I'm supposed to be doing with them.
At the moment, I have Vista 32bit installed on the computer, and I want to upgrade this to 64bit so I can use more than 3gb of ram. But when I run the setup files, I get an error saying that I can't install it because I'm running the 64bit files on a 32bit system.
I've tried creating a bootable disc from the three files, but I get stuck when vlite wont recognise that the folder I'm selecting has the right files in it, so I have no idea how to go down that path any further.
I rang microsoft to ask if there was any way around all of this, and the person on the phone said that because I've installed a 32bit operating system, my processor is now forever locked on 32bit, and I will never ever be able to use any 64bit anything.
Is there a way around all of this? If someone can help with the vlite issue that would be really helpful, but apart from that what should I be doing? Would getting the disc that comes with the package be helpful?
Thanks in advance

Ok, and what the woman said about once a processor has used 32bit it can never go back is utter bullshit right?
Is there a way to get a working version of windows using the update key and files I got? I bought it so I wouldn't be pirating, and I'm kind of hoping to be able to use the key so I have a valid copy of windows