Zurich to Amsterdam

Hi,

I planned a holiday to Amsteram, Belgium and Italy and the travel agent got us flights to Zurich. we need to get from Zurich to Amsterdam. How far is it and approximately how much does it cost? we are on a tight budget and are looking for the most inexpensive way to get to Amsterdam from Zurich. unfortunatley, we cannot change our flights, so we are stuck.

any help or advice would be greatly appreciated.

thx

Susan