The antenna can be found here:
http://store.mp3car.com/ProductDetai...ctCode=COM-008
I have been in touch with Hirschmann (the manufacturer) and today ordered an adapter from them. It's going to cost about $20/with shipping. The other options I found were all overseas and while cheap over there, conversion to the U.S. dollar put them all over $50 or more with shipping. I should have the adapter by the end of the month (they get shipments from the parent company in Germany twice a month). This car is parked for the winter so I'm really not in a hurry to get this installed.