As one SF to another,
I think you should start with the website.
www.aka1908.com. There's a feature that will allow you to search the chapters by state and region. I was able to find some information about the citywide chapter in my city. Calm down and be very very patient. From what I have experienced, it is very different from the process that other SF's go through to get to know members of the organization. Try speaking with the student activities office. They may have more information than you think. Also they may clear up any misconception about whether your school is affiliated with city wide chapters. If you have a contact with a member of the organization, contact her. But do all possible research first about where and when activities may happen.
I hope I have helped. I'm going through something similar. Just keep on keepin on.