I know that well - I was in a chapter that was never larger than 25, at a school where all the other chapters were well over total, which was 80!
We participated in formal rush, then ran informal rush in both the fall and spring - though I must admit it wasn't very successful
Our new members from formal rush were asked to bring their unaffiliated friends/roommates along to rush events - plus we advertised heavily.
It is VERY HARD to compete with big chapters when yours is the only small one... people wonder "what's wrong, why doesn't anyone want to join XYZ?" But keep at it and you'll get the right people, and they'll attract more of the right people, and before you know it you'll be growing.
-- Oh yes, forgot to add: If your Panhellenic keeps a no-bid list, get it, and get it ASAP after rush. Some of these women may still be interested in joining a sorority and they just got cross-cut. Invite these women to informal rush and see if you like 'em and they like you!
[This message has been edited by aephi alum (edited July 10, 2001).]