Our usual publicity consists of student drawn posters displayed in the local businesses. However, this year one of our classrooms taped a commercial that was played on the local cable channel.
Could someone in your group do a tape of students dressed up and talking about what will be at your carnival? You could then take that tape in as your "interview". Another possibility is to take some of the students with you - you would need parent permission/authorization.
Our PTO is sponsoring a spring carnvial themed "Around the World". I am going to request appearances on local morning shows, but can't think of a good gimmick to come up with that would give the interview more "zip" than the run of the mill "tell us about your event" interview. We are having people in costume, booths, inflatables, pizza, nachos, raffles. If anyone has ideas that'd be great!