How about if you find out where a craft show will be held in your area in the next few weeks, attend with a recruitment flyer and ask some of the vendor/crafters at that show to consider coming to your school show.
Also, what about Church bulletins or community center bulletin boards.
Or.....find out if it would alright for your group to post something at your local craft stores advertising booth space at a craft show. You may get a few more.
We are having a craft show at our school too and are actually calling it a holiday bazaar. In that case, we can also invite Pampered Chef reps, Tupperware, Creative Memories, Longerberger Baskets, Mary Kay, etc. Just a suggestion