Hi, I have a customer who has an office bolted onto their house. They use the office wifi in the house but cannot get a signal in all rooms. I think they installed some kind of booster but its hopeless.
The house is massive. Almost stately home size. I know there are the little Devolo plug in extenders that work over the 240v power sockets but firstly I have had mixed results with them and secondly I am not sure both buildings will be on the same ringmain.
I have also used the netgear extenders with the little antennas on with some success but I am not sure if they can be piggy backed like a a repeater or if each unit has to be within range of the source wifi.