Switzerland is a much smaller market than the UK or France. If you can't find what you are looking for you may have to go the the UK or France or online. I often by fabric online (or did when I was in CH).
Have you gone through the yellow pages and found all the fabric stores in your area?
There is a store in Etoy that has some lovely fabrics and a large selection. It's in the commercial area near the Hornbach. Schilliger also have nice fabrics. Not sure how "reasonably" priced they are. Oh, how I miss Schilliger....