When my wife was pregnant (our baby is now one month old), we paid on an average Sfr 400 for one visit including the ultra-sounds. So, you might be looking at something in the same range.

You will first need to call a gyno. This is hard to do as most of them are booked. But once you find her, you can go to her for the checkup.

Congratulations and good luck !
-Ip