I would use the tithing money to pay off the loan. It seems a tad arrogant to want to be the big philanthropist when you are in debt. And then before you have your retirement funded.
Then I would move to a cheaper state and buy a used house in a middle class neighborhood right by work.
On a personal note we were discussing the pitiful wages and high prices in the US this morning and were discussing The Italian Solution, the multi-generational home. One trash bill, one cable and internet bill, one pool-guy bill, one home insurance bill, one yard maintenance bill…but I suppose no American woman would marry my sons if they proposed that?