Regarding the need for a place to meet. I don't know the size of the town your school is in but maybe alums could host at least your chapter meetings in their homes until the problem is fixed or if any alums (I'm talking of the organizations not just the school)- if they own a business in town- maybe let you use the space? As for the unity- I think you just stated the answer in your post - all the greek organizations are out of a place to meet so that would be a prime reason for all the organizations to get together, form some sort of task force and find a way to get a new place to meet (i.e. fundraiser). If your sorority has been around since the 1800's- you must have a huge alum base to help you (and donate funds)! I wish you the best of luck!
Sue