Install the binary distribution of psycopg2 for the same architecture as your Python version.
Your Psycopg2 architecture must match the architecture of the Python binary you installed. So if you have a 32-bit Python 2.7 you must get the 32-bit psycopg2; if you have the 64-bit Python 2.7, you must get the 64-bit pycopg2.
This applies to any Python module that contains binary modules, not just psycopg2.