WIFI for caravan

Hi 

I am looking for advice for best solution to improve WIFI inside stati caravan. Site WIFI IS about 80ft away mounted on top of pole. Appears to be 72mb network but recieve about 6Mb outside caravan and intermittent speed inside. The nearest supplier mast (O2) is about 1.5km away. Caravan is metal box so not good for recieving WIFI so looking at installing an outside Antenna to recieve WIFI and deliver to router inside. KUMA recievers and netgear router? Would the a netgear WIFI 6 router be the choice and would it accommodate a USB connected reciever?

Thanking you in advance

Robert