Hi!
When it comes to the HSG, the workload really depends on the course you're taking. I assume it would be possible to have an evening job, say, as a waitress, but that would require a bit of German (which would improve really really fast). I have no clue about other employments, maybe you can check with the language department if they have any open position, say, for the conversation classes?
I am part-time in that area of Switzerland, so I'm sending you a PM with some advice for where to live etc right now