Raddy,
Just to answer your first question,
Yes, the man does move the space station when he pushes on it, just as the space station moves the man. The difference is that the space station has so much more mass (not weight - which is dependent on gravity) than the man that the man moves a lot more than the station does. This is an example of Newton's law "For every action force there is an equal but opposite reaction force." The action would be the force the man puts on the station, and the reaction force would be the same size but from the station to the man.
Hope that helps,
Kerry
