@davehc:
Regardless of how the Windows 7 product is purchased; full retail, full upgrade or OEM, the product key issued will work for either the 32 bit or 64 bit just as long it's the same edition ie, Pro 32 bit versus Pro 64 bit.
I have checked this on the different versions, editions and type sold. It will work on the downloaded ISO images that's burned to a DVD also.
@Diane: Your laptop must be rather old if it is only a 32 bit hardware system. If you bought it within the last two years, I'll bet you it's a 64 bit hardware system. Give us as much info as possible.
What make and model is it?
Here's a better link to downloads of the Windows 7 ISO image files. Just use ImgBurn to burn the ISO to a blank DVD. This is from the Windows 7 Forums sticky:
Windows 7 ISO – Official Direct Download Links