Long Range WiFi PLEASE HELP!!?

Hi,At a Campground they have wifi, but only on the porch can you receive signal. The Router is in the lounge ( in the attic) by a window, opposite side from cabins. I believe it is a D-Link, Kinda old. The cabins are a good 100- 150 yards away from the opposite side of the building with the router. Would it be possible to get a antenna to mount ( not looking to mount on the roof) so the cabins get wifi? It would probably be mounted on the opposite side roof too.