32 bit (float) audio files and 64 bit software are to completely separate and independent things.
The audio file bit depth is something you select based on what you're going to do with the file later. If you're going to do further processing then 24 or 32 bit is a good idea. If the file is for release to the listening public then 16 is usual, though 24 might be appropriate.
The version of the software you use is dependent on the computer you're running it on. You can't run 64 bit programs on a 32 bit computer. A 64 bit computer running 64 bit software will generally outperform a computer running 32 bit software.