Any simple way to turn an Android phone into a WiFi repeater/relay?

I work in a small building that can pick up a wifi signal from a nearby building on the same property, if you are in a certain spot. I was wondering if there was a way to set my phone up to take in the wireless signal where it is good enough to use and amplify it in the room so that I can use my tablet on wifi without sitting in the corner (which is impossible for me to do if I want to actually do my job).

I read about the DD-WRT router firmware being capable of such a task but the cost of getting started with this would be 60-75 bucks and if I have the materials to do it already in my house, what's the point?

Any help is appreciated.