If you use several different versions of python try using virtualenv
http://www.virtualenv.org/en/latest/virtualenv.html#installation
With the advantage of pip
for each local environment.
Then install a local environment in the current directory by:
virtualenv -p /usr/local/bin/python3.3 ENV --verbose
Note that you specify the path to a python binary you have installed on your system.
Then there are now an local pythonenvironment in that folder. ./ENV
Now there should be ./ENV/pip-3.3
use
./ENV/pip-3.3 freeze
to list the local installed libraries.
use ./ENV/pip-3.3 install packagename
to install at the local environment.
use ./ENV/python3.3 pythonfile.py
to run your python script.