Your sorority friends have graduating seniors in their chapters. Once they graduate, they will be alumnae. Thus, they can connect you to brand-new alumnae!
Talk to them now: they can send the recs on graduation day!
Your sorority friends at your school already got recs for their recruitment, so ask them for help. You can be introduced to their former sponsors.
There are tons of posts here about recs and recruitment. Contact your hometown alumnae Panhellenic for assistance with recs, too.
You sound like you're not sure about going through the process. Getting recommendations takes time and effort. Good luck!