Welcome to the madness.
I’d suggest going to the HMMWV forum and reading through the several hundred pages of posts on “what did you do to your hmmwv today” to see the kinds of problems that are common, solutions, suggestions, and more.
Once you’ve familiarized yourself with that, and are still brave enough to want to go forward, search classifieds here, ePay ads and ads running on fakebook’s several hmmwv-specific sales sites. If you post your TOWN, someone here is likely to say “hey, I’m just down the road and can help you.”
Oklahoma’s pretty yuge.
Good luck in your search, and post pictures when you find your truck.
Norm