Not really a German textbook, but if you don't have a copy of 'Ticking along with Swiss Kids' I would advise getting one. It is a really good introduction to Switzerland and Swiss traditions and has some basic flash cards in all four Swiss languages to help kids make friends. I have to say I found it really interstering even as an adult! More details here:

http://www.bergli.ch/shop/detail/ISBN-9783905252156