Wow! What a great collection!!
I would suggest the University of Illinois. They already have a dedicated collection of historic Greek materials for preservation, and I'm sure they would love to grow that collection!
http://archives.library.illinois.edu/slc/stewarthowe/
Illinois has the largest public university library in the nation, and up until very recently had always been the largest greek system in the nation, so it seems like a perfect fit!
Agreed that you should write a book on your findings. I'm sure there would be a large interest.