All of this reading would be pricey if you were buying the volumes, but if you are a university alumnus, you might check with them to see if you have access to their library. I've also bought a community library card from my local university. You can also speak to your local public librarian about getting inter-library loans. JASNA Canada has an online catalogue of books about Jane Austen and you can borrow from them if you are a member.
Here are three scholarly books that I've found worthwhile: