I am an exchange student here. I am holding a J-1 Visa to enter. My Visa is going to expire on June 18th. However, I am accepted into a 2 weeks summer music program dated from July 2nd to July 14th. I would like to know is it possible to extend my visa till then? Or I have to obtain another kind of visa?

If I have to get another kind of Visa, is it possible to do it in US?

Thank you.