I agree with the calling a meeting, nervewracking but worthwhile, write a list of the points you want to get across before you go in.
A couple of tips which I use, which may help without being confrontational:
When he interupts you, stop talking when he has finished speaking say 'As I was saying' and continue with what you were saying.
When he stares at your chest, if you are wearing a jacket pointedly pull it across your chest,
or,
bend your head down to your chest level and make eye contact with him. Most men look at women's chests (they can't help themselves, bless!) and think you don't notice, if you draw their attention to it they usually get embarrassed!
I'm not sure how old you are Serendipity but I suspect young, unfortunately it may be he thinks you're 'fair game', is there an older person, preferably male who could have a word with him on your behalf and say that our culture does not accept the way he treats you.
Good Luck