Who is Ramona Mueller from Drowning Ruth and what is their importance?

Ramona Mueller is the Postmistress of Nagawaukee, Ramona relies on safe small talk with patrons, such as "Spring's coming," but insults Amanda Starkey by declaring that her newly-returned brother-in-law, Carl Neumann, is lucky to have her to help with his daughter Ruth. Amanda considers herself the half-orphan's mother. Mueller is used largely as a vehicle for gossip early in the novel.