How long should I wait to ask about internship admission decision?

<p>I emailed the coordinator a week ago wondering about a decision and he told me I would get one "soon." I really need to know a decision within the next week because I need to register for classes and the classes I register for depend on this internship. Also if I do not get it I need to get in contact with professors about research for the summer, but i do not want to do that unless I am sure I was not accepted. </p>

<p>How long should I wait to send a second email?</p>