Hey Scruffy,
Sorry to hear your still having problems with that leak. It seems like a liner is your only solution, hope you can find one at a reasonable price.
I agree fuel prices are going to be insane, but a good alternative is an automatic coal stove. I took out my wood stove, and got a coal stove this spring. 3 tons of rice coal should get me thru the next winter for $840. Good luck with your pond.