I really don't have a lot to add, but just want to reinforce the growling part. Try to think of growling as "positive". Growling is a way dogs communicate. She's telling you she's uncomfortabe, in this case resource guarding (the sofa) so I would provide dog pillows and disallow furniture privledges. You may want to search for NILF (Nothing in life is free) posts here on GT and work with her as she may eventually be able to be on furniture without guarding.
If a dog growls and they are punished for it, they will stop growling. However, they may just go for the bite instead. I much prefer a dog growl at me and let me know we somehow have to change the situation, rather than get bit. Turid Rugass (sp?) also writes a lot about calming signals such as tongue flicks, lip licking, turning their head, etc. If she's exhibiting any of this, you can get a heads up if something is making her uncomfortable. Take it slow for now, she's seen a lot of changes in a short amount of time.
eta: I'm not a fan of crates unless it's for safety reasons. Some will tell you they like to crate train their dog so if there's an emergency, they are used to the crate. I never crate our pups and never had an issue, so I will never recommend crates.