Ok. gave this project a good think, here's what I'm thinking.
First of all, figure out much electricity you've got available. The 20W panel you've got is probably not gonna put that out under halogen light... I'm guessing you'll get 3-5W, but that's a guess. Can you get at the halogen light source, rig up the panel and measure the output? Use a DMM, measure the open circuit voltage and short circuit current (and let me know what you get).
Then set a bench power supply to the current/voltage that you mention, and start trying to drive different motors with it and see what happens. Coming up a good way to turn a spinning motor into a golf ball being hit is your domain, not mine
If you need to control the speed of the motor for whatever reason, put a sheet of cardboard in front of the panel.