WiFi isn't designed to go that far. Not only that, even if you can receive WiFi, the hotspot doesn't have the ability to transmit that far. Unless you control both ends of the connection, you are unlikely to be able to make this work reliably.
That said, you can extend the range of WiFi considerably by using something called a Yagi antenna. You can even build your own out of a Pringle's can. Lots of Google hits if you put in 'Yagi'.