I had trouble inserting the link of the thread I did on non-NPC national/regional social sororities (recruitment-based). So I copied and pasted most of the info below.
Since you are at catholic college, the college adminstrators might look more favorably on a sorority like Kappa Beta Gamma or Mu Epsilon Theta.
The thread on helping smaller GLOs made me realize that very few of us know about the national/regional social sororities who are not of the NPC.
General Social Sororities
Alpha Kappa Phi (Agonian) - founded in 1885, 5 active chapters (NY based);
www.geneseo.edu/~ago/
Chi Delta – founded 1990, 2 chapters (CA based);
www.chidelta.com
Kappa Beta Gamma – founded 1916, 7 chapters (mainly mid-west - IL, WI, MI);
www.kappabetagamma.org
Kappa Delta Phi NAS - founded in 1969, 12 active chapters (New England based - NH, RI, ME, VT, MA, NY); very closely affiliated with Kappa Delta Phi men's fraternity,
www.kappatalk.com/nas.html
Kappa Lambda Psi – founded 1980, 5 chapters (New England based - NY, NJ)
Iota Beta Chi - founded 1996, 2 chapters (Canada based),
www.iotabetachibeta.com/
Pi Nu Epsilon – founded 1914, 4 chapters (mainly east coast - NY, Canada);
www.geocities.com/sistersofpinuepsilon/
Sigma Gamma Phi (Arethusa) - founded in 1870, 4 active chapters (NY based)
http://www.arethusa.org
Niche-Market Social Sororities
Alpha Delta Chi (Christian) – founded 1925, 8 chapters (mainly west coast - CA);
www.geocities.com/SouthBeach/Jetty/3592/
Alpha Sigma Kappa (engineering) – founded 1989, 6 chapters (mainly central);
www.alpha-sigma-kappa.org/
Ceres (agriculture) – founded 1985, 9 chapters (mainly west, mid-west - WA, Canada, SD, ND, KY, IL);
www.ceresfraternity.org
Mu Epsilon Theta (Catholic) – founded 1987, 2 chapters (south – TX),
http://studentorgs.utexas.edu/metheta/
Phi Beta Chi (Christian) – founded 1980, 7 chapters (mainly central, east coast – TX, IN, NC)
www.phibetachi.org/
Phi Sigma Rho (engineering) – founded 1984, 20 chapters (west coast, central, mid-west, east coast – CA, OR, WA, MO, TX, IN, OH, KY, PA, NY, NJ, FL);
www.phisigmarho.org
Sigma Alpha Epsilon Pi (Jewish) – founded 1998, 6 chapters (mainly west coast, central – CA, AZ, MN);
www.sigmaaepi.com/
Sigma Alpha Iota (music) - founded 1903, 205 chapters (allows dual membership with other social sororities);
www.sai-national.org
Sigma Alpha Omega (Christian) – founded 1998, 14 chapters (mainly east coast, mid-west – NC, GA, IL);
www.sigmaalphaomega.org