get the mazuri brand lab blocks. i think they sell them in about a 5lb bag at petsmart. definitely get her a water bottle too--much neater/cleaner, etc. fresh veggies are great for rodents, but do not give them lettuce (too watery so it causes diarrhea) or citrus fruits. they can also eat a huge variety of left overs and other food items--see becky's rat food mix (stickied at the top of this forum) for ideas.

provide empty paper towel or toilet paper tubes for hides/something to chew. all my rats have the igloo things you can get at petsmart to hide in, although they like to flip them over and sleep in them upside down. i also give them empty boxes from granola bars, microwave dinners, etc.

if you decide to keep her, keep in mind that rats are social creatures and really don't like to be kept alone. a friend of the same sex will be greatly appreciated.