Yeah, unfortunately, Directed (the maker of the Starmate Replay) decided not to make additional car kits readily available for consumers (I guess since the Starmate Replay automatically comes with one they felt that additional ones were not needed).
A temporary solution... get the antenna, get a compatable cigarette adapter at Radio Shack (feel free to bring your Starmate in and test the adapters) and then get some double sided tape or velcro and use that to attach to your dash. This is until Directed gets those additional car kits released.
Good luck.