|Consider using home plug adapters. These circulate the lan over the house mains wiring.|
They come allowing ethernet connection only; or wifi (with or without ethernet cable connection option too).
If using ethernet only then - plug one into an a/c socket adjacent to the router. Plug one into any convenient a/c outlet in the room(s) where wifi signal is weak.
Connect the router to the adapter in its room via an ethernet cable.
Connect your Macbook to the adapter in its room also via an ethernet cable.
If wishing to extend wifi (with or without ethernet option) get the homplug wifi extender adapter for the distant room.
In the UK and Europe many use Devolo (they were the first); whereas in the USA/Canada Devolo is not available, but D-link, Netgear, and Cisco/Linksys make similar modules/adapters.
Belkin also make wifi extenders which rely on being able to detect the "master" router's wifi signal, and then then reradiate it. Personally I prefer to user the systems which are fed via ethernet (lan over mains) adapters; and then use a wifi adapter - still fed via the layover mains - for the distant room.
message edited by trvlr