BTW, a 'round trip' train ticket to Zürich HB from the airport is good for 24 hours and all of your travel within the two zones including the airport and most of 'downtown' Zürich. If the weather is sunny, get the third zone that will take you to the top of the Ütliberg.

Last time I returned on a flight I noticed that there is a Swiss Tourism office just past the baggage claim and customs. YMMV though, as there is a bit of construction going on.