I know what you mean. I also love tennis and initially battled a little bit to find the relevant club and partners. The best bet is to advertise yourself in the local club so that you will get people to phone you or join the club as active or passive member. Then you get at least chance to make appointment with players matching your level.

In winter on the Halle you pay more but if you are good and have a licence you can play the local tournaments.Check www.mytennis.ch . Else you can just play social games with partners...

In spring and summer you can join the club and you would be able to play interclub and club championship.

As far as squash is concerned check at : www.vitis.ch

I would meet you up and play unfortunately I live in Baden about 40min from Zürich so distance wise it is a bit a problem.

Hope you will get all this right Do not hesitate me if you have any questions regarding tennis. I am willing to answer them.