Personally, I'd offer a weanling rat and then a rat pup 4-5 days later if she denies the weanling. Since it's already on two prey items, you can throw a second in as you see fit. A rat pup is about the size of an adult mouse, so two rat pups or a weanling rat and a pup should be appropriate. When you get a good weight you can probably move her up to smalls.

I don't know what size of a rat a hopper is, I'm only familiar with mouse hoppers.