How old is the bitch? Has she always done this? Is she overweight at all? Just wondering in case there's some medical cause for the vet to investigate.
I've a young terrier, only a year old, who snores fit to wake the dead too. The only time she doesn't, or at least only quietly, is when she's on a chair or other soft surface. On the carpet or floor, she's loud. She's perfectly healthy. That suggestion may not help, if you have to give up a chair, if that works at all!