Hi and Welcome! I'm fairly new around here, too. I began my AI search in August after contemplating it for some time.
I think that your experiences with Gamma Sigma Sigma would be looked upon postively. Especially if you have leadership experience. The alumnae will see that you are willing to share your skills with the group.
Some NPCs require that you be out of school for a number of years before pursuing AI, so you should check up on that first. As a current student, you may not get much response right away. Hang in there though! My advice is to visit the inter/national websites. Most of the ones I have looked at list all active alumnae chapters/groups/associations as well as college chapters, so you should be able to easily find what sororities are active in your area.
Best wishes for a great AI experience!!
Welcome to the "I check my e-mail every 5 seconds club"
LM