This happened to us last year. you can take the table to your local glass repair place and they will charge you a LOT of money to replace the glass for you, or you can do as we did. We went to the local big box hardware store and got a piece of plywood (this store cut it to size for us) and some L-brackets.
We screwed the brackets to the plywood and then fastened the plywood to the frame of the table. We got a piece of pretty oil cloth for a table cover and that worked fine for us for the rest of the summer.
Lauren Gallagher
April 2008