Hi debs,
If I can inject a little advice concerning what I would do in that situation...this is what 'I' would do, not necessarily what you should do...I would NOT move back in with my parents...they understand you have a life of your own and are trying to make it a good one...they would NOT want you to just heave it aside...
initially I would assist my father and sister ( as she is living there ) in getting another job...there are plenty of ways you can help...send out resumes on their behalf, scour job banks, even take out a couple of local Ads in the paper under ' work wanted '...etc...
if push came to shove and their back was up against the wall...I'd offer to help them cover their mortgage and bills insofar as I could until they were stable...and continue to assist in getting them gainfully employed...
moving back home would not be an option I would even consider.
Eg ;)