First of all, those statistics are really misleading. I've spent a fair bit of time in la Suisse romande, and I've found that half the people speak English really well, and the other half speak it competently -- easily well enough to understand and make themselves understood, which is really all you want for sarging. If you're in some really tiny village, you may run into very few people with a decent command of English. Otherwise, at least according to my experience, I think you'll be fine.
At any rate, use your time in Switzerland as an opportunity to work on your nonverbal game. Look to make whatever improvements you can on your body language, facial expressions, eye contact, voice tonality, and even kino. Think of it, even in a case where the girl speaks virtually no English, as a challenge to see how far you can take things without the usual verbal crutch.
Another thing I would recommend, if you feel you're encountering a shortage of women who speak passable English, is to find a wing who speaks French and English. Once when I was in Switzerland, I found myself in a small, rural town where English was scarce. But I was traveling with someone who spoke both languages. We went for a drink at the town's pub, and there was a beautiful girl there, and my wing helped with translation and to lend me an air of familiarity. I focused on my body language, tone of voice, eye contact, and, of course, kino. After a little while, my wing made himself scarce, and by then the language gap between this girl and me didn't matter. Comment dit-on "f close" en français?
Btw, thanks again for your comments on my thread. They were very helpful.