Sadly, I don't think to many people have had your plight which is why no one knows the answer here.
You may find going to an Apple Store will be the cheaper way to go on this system.
Between the difficulty opening it up and the cost of the part their bench fee and parts cost I think will be lower and less stressful on you ;-}
If you still want to go for it. Give some of the part houses a call or email. Don't forget about IFIXIT here as well.