You can give a bit of cheese as a treat, even though my rats didn't particularly like it. Bread is not very nourishing, but if you spread it with a THIN layer of peanut butter, she will love that and it's good for her.
Basically feed her anything healthy that you eat - veggies, chicken, cereal, fruit, rice etc. She also needs hard things to wear her front teeth down as well. I used to crack a walnut a bit and give to my rats. They loved getting it open! Do not feed her hamster food, as that is full of alfafa that rats cannot digest or use.
Put something really good, like small pieces of banana,(or the bread with peanut butter) in the palm of your hand, then put your hand in the cage and let it lie on the cage bottom. She should come to get it and learn that your hands mean good things.