In that case, I wouldn't worry about installing for all users. I'd build from source and configure with the --prefix argument. Then I'd start Django using that specific Python.

Or, since Django on Python3 doesn't seem production ready yet, I'd "upgrade" to Debian testing or unstable, and hope that by the time Django became production ready Py3.2 was in Debian stable.

If you're currently on stable but are comfortable running a mixed system, you can install python3 from testing to get 3.2.