Normally the only reason a program will not work in 64-bit is because in actuality it is a very old 16-bit program (32-bit runs 16 or 32-bit programs while 64-bit runs 32 or 64-bit programs) This may be the case of your software.
Retail versions of W7 come with both 32 and 64 bit DVDs but if your system came preinstalled then I am afraid downloading it or borrowing the DVD of a friend (but then using your key) are the only options.
Another possibility, besides reinstalling with the 32-bit OS, would be to create a virtual 32-bit machine under your 64-bit OS. But your 2gb of memory and celeron cpu might not be powerful enough to run the virtual environment very well; plus you would need XP disks to install in the free virtual engines or you would have to upgrade to W7 Professional to get it's Virtual PC - XP mode.
Be sure to make note of your Product Keys before you reinstall. Also you will need to back up all your data. And you will need 32-bit drivers (most will be found automatically but if you can download them ahead of time it might be helpful). Also you will need all the program disks to reinstall them; this includes any programs that came preinstalled on the computer but are not part of the W7 OS (such as Acer software, onscreen volume displays, touchpad controls, trial programs, etc); if you can't find these on the Acer site then you may need to find replacements or do without.