B.M.
Okay I know that this may not be as helpful to you would like but my mom is a professional clown. She doesn't live in town but I have talked to her about this and most children don't even care what the clown is going to do until they are 3 or 4. I understand you will have older children there but a clown may not be your best pick for a restaurant. Clowns can be very expensive. You can look in the yellow pages and find clowns in the area but the experience I have had with clowns in this area hasn't been pleasant. I hold high standards for clowns because I have seen many clown parties. Some children will be scared of the clown. My son isn't a big fan of clowns unless he watches my mom get ready then he will hang out with her but if there is another clown around he isn't happy.
Good Luck
B. M.