Added a celing fan in bedroom, need to wire for switch
I would suggest a universal ceiling fan remote control that uses a battery for power. It comes with a sender and a controller you connect to the fan. The sender works just like a hand held remote except you mount it in the wall. So all you really have to do is to leave the wiring the way it is, use a cut-in box to mount the sender and connect the receiver to the fan. I don't have a link to a site but they are in all of your big box hardware stores. 

Good luck