Because you are needing the motor assembly and all, new, ebay, or a parts service for used items is about your only option for restoration to full functionality.
As a plan B, you may consider replacing the mast (as described elsewhere on this site) in your origional non-working unit. However, during the installation process, install the mast while extended, rather than collapsed. It will still be inoperable as far as raising and lowering, however, your reception will be good. Just watch-out when you go through a car wash.
Best of luck,