In the Biopython installation instructions, it says that if Biopython doesn\'t work I\'m supposed to do this:
export PYTHONPATH = $PYTHONPATH\':/directory/where/you/
You wrote "(or everything of it past the ~ directory)". I think you need to use the full directory path. And ~ isn't expanded immediately after a ':', so use $HOME instead:
export PYTHONPATH = $PYTHONPATH":$HOME/directory/where/you/put/Biopython"
(Note the use of double rather than single quotes so $HOME is expanded.)