Hi ngfan,
In your situation I'd check the gulfholidays website rates for using the Movenpick - in many cases GF will give you a voucher for transit use of a hotel.
Cedar Jet has been my best FT resource on hotels for transit at BAH, so you may want to search his profile for threads regarding BAH and the Movenpick.

That said, the GF lounge (J and F) is open until these late flights depart, and include day beds which may be OK if the F lounge is not overcrowded.

If your travel agent can confirm you can collect a voucher for a transit hotel, try to get GF to confirm a booking at the hotel, in case of problems at the transit desk. No doubt you could get it sorted out in the lounge ^

Cheers (please post a report of the trip and your success with arranging the limo and/or hotel!)
Ben