Help with picking up free wifi on Apple iPad Air 2

I have an iPad. I am camping in a remote site but it does provide free wifi. The wifi only reaches a limited area around the clubhouse. I have the user name and password but my camper is about 1.5 miles away. How can I increase the signal strength so I can get free internet at my trailer. There also seems to be somebody close by that has unlocked Internet but it still requires a password. I have downloaded a bunch of wifi apps to my iPad but have no idea how to use them. Can somebody please help me?