There is no support for WinTV in media car for either the rado section or the TV section.
Now some people have reported success with radiator and the the FM section of WinTV. However I have yet to get that working for me.
If you have a Radio card that radiator supports, you can use Confused's radio supplement to give your self a temporary radio fix as an external app.
It works well and I have used the USB radioExtreme in this situation.