A few things:
1. due to not making quota and deactivations are you currently under ceiling?
2. even if you are not under ceiling you have the right to pledge quota through COB for the entire calendar year after FR.
I suggest you pledge up to quota immediatly. I undertstand that the chapter may be worried about looking bad doing COB but do it quietly. Don't plaster flyers on the quad, identify super freshman or steller sophomores (maybe those in leadership positions, on a sports team, or a highly sought after campus activity) and get thsoe handful of women to pledge. Yes their new member experience will not be the same as those who went through formal recruitment but these women can huge assets to the chapter!
3. contact your National immediately! They will help you out, just be prepared to be flexible and make some changes to your recruitment program.
Don't worry too much. I helped a chapter that missed quota by a large amount last year not only end up making quota this year but moved up 3 spots in rushing strength. It can be done and it sounds like you want to be successful so I think things are going to turn out OK.