I've never really known if this stuff:
http://www.fixaleak.com/pools.html
works, or not. But given what your options are, it might be worth trying. Be *SURE* to read the instructions on the page above, before deciding to buy. Here are two links to Amazon for the product:
#1 Marlig Fix A Leak Pool Leak Sealer - 32 oz
#2 Marlig Fix A Leak Pool Leak Sealer - 32 oz
If you do use it, please let us know whether it works or not.