I doubt you can burn vista onto a couple of CD-R's, you will probably need to boot from the disc, which i dont think you can do with Vista burnt on a CD. I could be wrong though, if im not here's some links to the dvd iso if you get dvd burner.
If you have a 64 bit processor you can run either (I have the 64bit ultimate if you need, but only a dvd image). If you have a 32 bit one you need the 32 bit version (x86)