[Koha] Search server for children's books

We have been using the Seattle Public library Z39.50 server and it finds most of what we want. There are some books that are not found. Specifically this one, 978-0060573829. Does anybody know of a good server I could use for children's books? I tried the Madison WI public library server but it times out for me. I never got a response about my question if there was a way to figure out if anybody was logged on the Koha staff client. Seems like this would be a useful addition to Koha. Thanks, Paul