You will have to install the 32-bit version of python because the 64-bit version does not install the 32-bit binary or .dll. You will probably also have to setup a separate environment (make a .cmd file that changes PATH, etc and run all of the 32-bit stuff from there) that only knows about the 32-bit binary and install all of you site dependencies into this 32-bit environment including 32-bit py2exe.
Or you could just get Virtual Box, install a 32-bit version of windows and setup your 32-bit build environment there. You could also install a Linux distro and use wine to build the 32-bit version if you don't have a extra Windows license laying around.
