Go to your nearest quality bookstore and ask them if they'll order study books. There was a store around here that would order anything and they had huge listings of books used for everything. It might not be on the shelf, but they may order it.
And you probably won't get that service for some huge chain bookstore.
I've got a great German grammar book by Berlitz that was old when I got it. I don't think the grammar has changed, but some phrases have since it was new.
Dave