Welcome to the site Elisabeth. You have come to a good place for tips and knowledge for your Z. Would love to see some pictures of your car. We are all pretty much Z daft on here and like finding old cars and new owners.
Sorry to hear about the window. It's a job z owners are pretty familiar with. Like the members have said, if you do have a chance to post some pictures, it would really help to assess what might need done. Some scenarios:
Ripped or Torn - You can actually patch it up or a new one can be bought and zipped in provided the hood is an original bmw hood. If its beyond repair, there are a few options for new ones for around £100, less for a second hand replacement. If so, there are a few members who break Z3 cars and may have them available.
Too cloudy to see out of - It might just need some product rubbing on.
The zip is unattached from the Hood - Sewing Kit time
What ever happens. There's a decent fix for it, absolute worst case, a brand new hood and window is around £350 fitted.
Good luck!