Charlie, regarding the leak itself: you can buy a cheap can of this stuff (forget what its called), but it glows under a black light. Its specifically for finding leaks in AC.

you just attach it like a refill can and it enters the system.

You then just pick up a black light bulb for a buck or two and use it to find the leak. Turn on the AC and shine the light in the engine bay, or if that fails, under the passenger side dash. Obviously a darkened garage, or evening outside works best.

If its in a spot that you can get to, it can easily be patched with a dab of high pressure-rated epoxy.