Rebecca-
First, welcome to Greek Chat! You'll find LOTS of wonderful people here.
When I read your post I thought that it was almost exactly like my story! I am a 2000 AI of AOII. Before beginning my search I did not know any AOIIs but I contacted IHQ and explained that I was interested in learning more about AOII and getting involved. I too was in a local sorority while an undergraduate (they affiliated with an NPC sorority but I didn't want to affiliate - long story!). That's the wonderful beginning of the story in a nutshell.
I would definitely recommend contacting IHQ to get more information as well as letting IHQ introduce you to local alumnae.
Feel free to join us on the AOII board if you haven't already
Sarah