Perhaps I am a bit confused, but I understood that you were trying to get information from the Room, and supply it to your Family inside that room. If that is true, you would be using Instance Based parameters which would not require the Family Symbol. If you are trying to set Type Parameters, then you need to get the Family Type.
ElementType fType = doc.GetElement(famInst.GetTypeId) as ElementType;
If this is not what you are trying to do, could you please explain a little more on what you expect the result to be?