Wi-Fi projects

I have a project that I am struggling with.

It is a bit geeky.

 

The goal is to get pick up a wifi signal at a couple of miles from the source.

My expectation is that I will have a couple parts to this; a wireless router, a cantenna, and software to possibly break a wi-fi password.

 

For the cantenna, I am thinking about this: http://jacobsalmela.com/wi-fi-cantenna-2-4ghz-how-to-make-a-long-range-wi-fi-antenna/

I do not know what range I should realistically  hope to get.

 

Instead of a wireless router, I may go with a raspberry pi option