i have been learning High German for 2 years (on and off)
I try to use it as often as i can but i realise the swiss people my age,either speak excellent english and/or they want to practice it with me.
I don't mind as I tell them i will answer them in Hoch Deutsch.
Last week i was with swiss friends and we spoke a mix of english, german and swiss german. at one point i couldn't tell the difference between the swiss german (zuri-deutsch) and the high german- i felt quite proud as i think subliminally i was probably understanding the zuri-deutsch!

I know many expats who speak crap german but have integrated very well. They use body language and humour for example. And others who have gone to classes to learn high german but are frustrated that many swiss prefer to speak english or swiss german, rather than high german. Thus they are discouraged when they feel the efforts they have put into learning high german hasn't helped them with "integrating"
anyway, my point is, that communication is much more than spoken language and i think integration is alot to do with your own efforts.