Brad:

Yes it is possible to buy a new mast. You can get one from the dealer, although I was able to get one through my local import parts place (had it in stock even). It cost me $32. It is easy to put in. Easiest with a helper, but not required. Put the motor back together and put it back in the car. Turn the key on, and the radio on. Then take the top nut off the "hole" in which the mast fits. Fit the mast tail down into hole until it stops. Have the helper turn off the radio, and if you are lucky it will catch and pull the mast down (if not repeat and try to get the "teeth" on the mast tail in a different orientation to get grabbed by the motor gear). Put the top nut back on, and test it out by turning the radio on again. This should work.