Strudel, it might help you to find a sitter if you give a little more information, for instance:
Are you looking for a sitter who takes your dog into his/her house, or for a sitter who will move into your house to care for your dog?
If the former, can your dog live with other dogs, cats, children? Any restrictions?
Would you consider 'Hort' type care, where there are several/many dogs cared for in a family-like setting?
Are kennels a possibility?
Are you in Zürich city, or elsewhere in the canton? Are are you willing to travel?
Hope you find a good solution...
Two platforms listing sitting services: http://petsitting24.ch https://www.betreut.ch/tierbetreuung
Be aware that with both platforms one must pay a subscription to get the contact details of the sitter .