If it says Windows 7 32-bit it's 32 bit.
Currently you can't upgrade from 32 bit to 64 bit, you can only upgrade to a different version of 32 bit (ie: You can go from 32bit Home Premium to 32 bit Professional, but you can't go from 32bit Home Premium to 64bit Professional) (What I mean is ------ You can upgrade your current 96-page booklet to a better quality 96-page booklet, but you can't upgrade your current 96-page book to a 128-page book... comprehende?)
Hope I helped
(Basically, to sum it up, you can't upgrade 32bit to 64 bit.)