[AlethiaSi]

ok first of all, I've been in a similar but different situation. My local sorority had SERIOUS lack in numbers, a bad rep, our house was closed... it was bad, I/we revamped things by actually having parties and getting the word out. Now, since you dont' want to do that, some other things we did that might be helpful:
FACEBOOK! this is an invaluable resource, create a group, contact girls, get the word out
WEAR LETTERS! have each and every sister wear letters as many days as possible, we had a letter day, where everyone HAD to have letters on.
During recruitment or any event, we had each sister bring at least 1 girl to the house, or event. I would talk to girls in my classes, on campus, on line for food, anywhere, i met some of our best girls that way (I was an unabashed recruiter lol) we put up posters for events, throughout the semester invited girls to things, got to know them and then they would come through recruitment and then bring friends because they knew what we were all about.
Now, I know that there might be different rules for recruiting throughout the semester at other schools or in other orgs, this worked for us and we were allowed to do it, just a side note.
if you'd like to talk more about this, please don't hesitate to PM me