If the covering is the only thing that's damaged, call an upholsterer to see if he/she can find fabric that matches and make new cushions. Or, alternatively, get some big (22") throw pillows in a coordinating print. Make sure they overlap slightly across the back of the sofa, so it looks sumptuous.

I agree with ASV. Your dog is bored. So that is the most important issue that you should address. Otherwise you'll keep upholstering the sofa or buying new pillows.
You could try getting her a Kong to keep her attention on something else. And if there's a dog walking service near you, let them take her on a long walk when you're at work.

they have something you can put on them so they wont eat them . its like a powder i think. not harmful... its for pets so they dont eat things.

I can attest to the fact that it doesn't work! It is called separation anxiety, and yes, there are medications for that. Does the dog chew things at other times? Or only when it is left alone? If it is crate trained, get a crate for a larger dog so there is plenty of room or use kiddie gates to make a safe area for the dog.

I vote for replacing the sofa, because it will be a miracle if you can find matching fabric to recover the cushions and pillows won't cover up the damage once someone sit on the sofa and buy a crate or gate or both.

Replace the sofa .... crate the fur baby!

Don't replace the until after you solve the chewing issue.

replace the cushions, and either crate the pup, or get some gates so that they don't have access to the sofa to chew.

separation anxiety is something that needs to be addressed, though. dog's not bored, dog's worried you won't come back.