I don't know which advice you are referring to, but if you have a Vista Ultimate disk it should have the 64 bit version on it already according to MSFT.
You can't upgrade from 32 bit to 64 bit.
To install the 64 bit version you will need to do a clean install by booting with the Vista dvd.
Save all your data before you start, you will need to reinstall all your programs.
You didn't get "jipped". When you buy Vista OEM you get either 32-bit or 64-bit, not both. You should contact Cyberpower and see if they will allow you to upgrade to 64-bit Vista... since they are the OEM you purchased from. They may provide you with a free 64-bit upgrade or possibly provide it for a small fee. (Smaller than purchasing the whole thing at least).