Can anyone recommend a good travel agency/tour service for travel to Brazil?

I would like to visit Salvador( and other areas in Brazil) and I would like to really see the points of historical interest, among other things. I am looking for a company that will provide us with guides who can speak English WELL and who are knowledgeable about the local history. This company should also be able to place me in a hotel where at least more than one worker speaks English well.
Sincere, polite, constructive answers only please.