Hi marsilinghoo,
I guess this is your first time to Switzerland?
Zurich and the other major cities like Geneva, Bern, Lucern are expensive. So are the major tourist places like Interlaken and Zurich. But I've found the smaller towns and villages to be quite reasonably priced actually: very decent accommodation for SGD 200 (sometimes less!) per double room per night (free breakfast is standard), and meals (lunch or dinner) for about SGD30 per person. Accommodation can be actually cheaper than northern Italy!
Knowing me, I would say just be adventurous and go around on your own, either rent a car or go by train. But if it is your first time, and most Singaporeans are not the adventurous sort and we are a very conforming people (always doing things the standard way), then you may consider joining a Switzerland only tour. There are many bad tour agencies around; but a few reputable ones offer quite ok prices and good itineraries at the usual expense of inflexibility, crazy waking hours, and the touch-and-go feeling.
If you *really* want to visit a country and experience the culture, the food, the people, then you should go on your own and not join a tour group.