Can you get above the ceiling ?? in the attic above?
Well that would be too easy, right? You will need to run a wire from the box you will install in the ceiling that will power and support the fan, to the switch in the wall. To run the wire if you have no access above, you will need to fish the wire through. To do that you will probably have to cut some holes in the wall and/or ceiling and then patch them/repaint them when you are done.