just take ur credit card with u and make sure that the limit is above CHF 3000.-
you may need less then that. but if one travel on holidays its always good to able to be afford what ever they may like.
i can make an example for you .

if you travel on the train from zurich to bern, round trip is around CHF100.- =(QAR 350)per person.

rent a car wll be around 120- 200+ per day.
remember gasoline is way more expensive than in qatar. you may need at least chf70-90.- to have a full tank

your best bet is to get a (GA) General abo. for a week. this can take you all over switzerland, on any buses tram or train.

eating at a good restaurant would cost around
CHF80-120 per person.
you can also eat at any take away or so called street food which will be around chf15-30 per person.

as for shopping, depends on which brand you like.
make sure you buy some shoes from there cus you will never find better shoes here than there , so when you are there, make use of your trip and get some good shoes. :0)

any further info let me know.