Hi
Thanks for the PM but I'm not really sure about any of your questions! There is a transit hotel where you can get a room by the hour, but not sure about the lounge. I would suggest ringing Gulf Air and asking, including about the tour as they could arrange something for you.
The airport is small but the duty free shopping and GF lounges are good, but it's not a place I would choose to spend 7 hours!
Be warned that Bahrain is going through a troubled period politics-wise, and whilst you won't be concerned for safety or anything like that they seem to be adopting very stringent (and completely unnecessary) checks on who is allowed into the country. For example a friend of a friend was denied entry because she had been born in Tehran despite holding a New Zealand passport and put straight back on the plane to London. If you do want to do a tour, I would recommend getting a visa in advance (not at the airport) via the Bahrain Embassay in Lonodon (Google it).
Enjoy your trip, it is a nice country with lovely people.