How diverse is the campus you're currently on? Also, how many minorities are charter members?
The reason I asked this is because (in case ya'll didn't know), I'm African American. When I joined OPA, it was already a pretty diverse group. My chapter's charter members are Caucasian, African American and Indian American (people decented from India, not to be confused with Native Americans). Showing that they were a very diverse group, they were able to recruit those who wanted be in a diverse group as well as those minorities (like myself) who also wanted to be a part of that group. It's worked well to this day.
If you and other sisters know people of any color who would love to be in this part of the group, try to reach out to them and promote how good it would be to be a part of the sorority. I was recruited by one of my best friends (who is Caucasian) who thought I would be good for the sorority. And then those who love it will pass the word and invite their friends.
Also, do not forget the non-traditional students and grad students. While I was in undergrad we had a member who was a married mother of two young boys. Patti, who's now one of the national officers, pledged OPA as a grad student (and a RHD of a residence hall of freshman girls!).
I hope this helps and I hope I didn't sound offensive (that's not the case). Good luck on the new chapter!!
