Nighthawk AC1900 Wifi Extender setup

I have an Apple Time Capsule wi-fi/router/backup. Great unit, but has no capability to add an antenna and it just doesn't cover my three buildings. Would this Nighthawk work OK with the Apple unit? The main house, garage/office and art room cover about 5000 sq ft.  and are no more than about 20 feet apart. Stucco and plaster walls.

Other suggestions?