As far as I know: Most Intel Atom Chips will support 64-bit Operating Systems if you install a 64-bit OS. Most Linux distributions do have 64-bit edition.
It is fine to run 64-bit OS on a 2GB CPU (just a little bit slow). I have got a laptop with Intel Atom, but, some how, you may have some problems with hardware not support 64-bit OS if the computer is not designed for that but it is usable. You should run 64-bit OS only for experimental purpose only.
Have you googled? I got this information from google.
By the way, Looking at this:
Code:
capabilities:
64bits extensions (x86-64),
...
4GB+ memory addressing (Physical Address Extension),
...
it does seem like your CPU is 64-bit compatable and you can buy more memory than 2 GB but on some motherboards don't support RAM more than 2 GB. Proceed at your own risk.