Were all your snakes in a rack system? Keep in mind I'm no expert, others will chime in.
From what I know, quarantined snakes aren't kept in the same room. If your whole rack was exposed, if possible I would separate them out. But if not, they were all equally exposed and could be quanrantined together. BUT whatever this is it is deadly. I would take every precaution.
I think standard quarantine is 6 months.
You can buy whatever you like, just don't expose them to anything your collection has touched