This will be arcane and troublesome but why not?
If I had no limit on time to fiddle I'd try the wr850g as a WAP.
First I'd install this -> http://www.dd-wrt.com/wiki/index.php/Flash_Your_Motorola_WR850G and then try to use this router as a WAP. How? GOOGLE THIS -> How to use a router as a WAP.
You might get lucky and be able to get this as a WAP to move closer to their location.
A bridge is likely to be the best solution.