As the link you posted to states httplib2 is not a standard library that comes with Python you have to install it first.
To install httplib2 in Python 3 you can use (Ubuntu):
sudo apt-get install python3-httplib2
or pip
pip install httplib2
Other instructions for direct download here: http://code.google.com/p/httplib2/wiki/Install
Then make sure it's on your PYTHONPATH.
Then just include it:
import httplib