I too thank you for the post, and I hope you keep us updated.

But. . . . to begin the “jumping all over,” I don’t think you really answered the question about what unexpected events happened since you took out the loan.
Your loan went up, just as it was supposed to. You fixed up the house, which should have been expected if the house needed it. You mention the $5000 plumbing problem. I have some sympathy there, but occassional costly problems are an expected part of homeownership.

If nothing has changed with regard to your income, do you really expect GMAC to re-write your agreement?