The Ubiquity antenna listed below works extremely well. I am in a campground where the signal in the RV "exists" but only if I sit in the front seat and it will not stay connected. I added the NanoStation plus the air gateway and I have a -40dB (very good) instead of a -99dB (very bad) connection. You don't have to do the wireless part but since I use multiple devices it's very nice and the entire setup cost me less than $80.
http://www.amazon.com/Ubiquiti-NanoStation-locoM2-2-4GHz-Outdoor/dp/B004EGI3CI/ref=sr_1_2?ie=UTF8&qid=1442843786&sr=8-2&keywords=ubiquiti+loco+m5