Hector
A 1242 configured for bridging using the "A" radio and a single patch antenna for both the root and non-root will work. just mount the AP on the inside wall of the building and the antenna on the outside you should be able to connect the antenna to the AP using the pig tail on the patch antenna.
remember you nee clear line of sight and the antennaas need to line up.
Good Luck
Bill
