Wow, that is really incredible! I'm glad you wrote to the manager.
That said - you may know that Border's is going out of business. They are having HUGE sales on all their books. Might be worth a look at their web-site and see if they have any books on special needs children (or anything else, for that matter), and score yourself some bargains.
Maybe the Barnes and Noble lady thought that with Border's going out of business, B&N's own business will pick up. She might find herself out of a job, though, if that manager really chooses to act on your complaint.