If you are not a formally recognized group on campus, see what you can do to change this status. Talk to the campus Greek adviser. Perhaps you can get provisional status as a member chapter of the Campus Panhellenic, or you can propose a Multi-Cultural Greek Council (men and women) if one does not already exist.
Or you can attach yourselves (with their permission) to a multi-cultural organization on campus.
Example: When AEPi (historically Jewish fraternity) first colonized at UCF, our Fraternity Council did not officially recognize them right away. Their colony did a lot through the campus Hillel to gain campus exposure and get their name out to the campus at large and potential brothers, to secure rush locations on campus, etc. Meetings were held in the president's dorm room. Eventually, they were recognized by the university.
For now, some things you can do to promote your organization:
- Wear letters on campus
- Plan an event at a local gathering place. Maybe get a private room at a local restaurant. Take out an ad in the school newspaper inviting prospective members to a meet and greet here.
- Compile a list of potential sisters based on the suggestions of your members.
- Invite these ladies to off-campus bbq's, community service events, ice cream socials, etc., that can serve as rush events.