This might be a bit late for you but there is a drop-off childcare facility, called Chinderbahnhof, in the main Bern train station. Here's a link to an information page in English:
http://www.chinderbahnhof.ch/fileadm...glish_Page.pdf
I don't have kids yet (but have one on the way so I've been researching childcare options) so I haven't used the service, but it looks like the sort of thing you are looking for.
W.