retractable antenna

The antenna on my I30 had been bent for some time and wouldn't retract fully. That problem was solved when it broke the other day. While it's no longer in one piece, it is still "attached" by the cable within.

Does anyone know what I must do to fix this problem? Is it possible to replace just the metal casing and keep the motor unit? Is it difficult to do necessary repairs? What is the cheapest way to repair the problem? Lastly, is there something I can do in the meantime to disable the "automatic" nature of the antenna to allow me to turn on the stereo again?

Thanks for any help you can provide.