If I understood the OP correctly, he is saying that he has apps he wants to run on Windows 7 that don't run on Vista x64 but ran fine on Vista x86.
32 and 64 bit versions of Windows 7 come on separate disks. So, if you only got one disk as an upgrade for a 64 bit vista system, it is probably going to be only Windows 7 x64. If your programs won't run on Vista x64, it is highly unlikely they will run on Windows 7 x64.
Your Windows 7 x64 key, (if you got a key) is supposed to be good for both 32 and 64 bit versions of Windows 7. So if you could download 32 bit media from some other source, you could do a clean install of the 32 bit version and activate it with the key for the x64 disk (again, assuming you got a key for it, as I'm not sure how these OEM upgrade versions are activated).