Star--
I deal with chapters like this sometimes, and my own chapter has gone through this.
#1) Don't sacrifice quality for quantity. It will end up destroying you from within.
#2) Having fewer members, while it looks different from the larger groups, can have its advantages. As someone else said, you can put together the best recruitment through hard work. Set realistic goals for your chapter, and then follow through on them. If you don't make quota, then COB to total. Try to target areas on campus where you may not have tapped into for members. You'd be surprised the number of women who would join a sorority if they knew more about it and didn't have to "come to the sorority".
#3) Make sure you emphasize the benefit of your national organization. Have alumnae or women from other chapters come for recruitment. They needn't be involved in say a skit or such. They can just be there to meet women, talk you up, and maybe serve food and drinks. Make sure you distinguish them.
#4) Take every opportunity to get your name out in a positive light on campus. Send notes to students on campus wishing them luck on finals. Sponsor a coffee break during mid term study periods. It only takes a chance meeting to find your next sister if you're looking for them.
Hope this helps you...I feel for you
If you'd like to talk, feel free to PM me.
Heather