Help with WRT54G v2 and Cantenna

Hi this is my first post here so please bare with me. At my house they do not offer high-speed internet but about a quarter of a mile away they have public wifi. So after reading off net I built a cantenna. So now here is my problem I just bought a Linksys WRT54G v 2 Wireless Router, Access Point, DD-WRT v23 sp2 loaded. 200 MHz; 16MB RAM; 4MB Flash, 250MW POWER off eBay. This is what I would like to do. I would like to be able to pick up the public wifi from the router and distribute it throughout my house using the same router and pick it up for use with my laptop with built in wireless card. The problem is I have no idea how to set up my router to accomplish all of this. Any and all help would be greatly appreciated.
Thanks
Lenny