I love rats, they are so loving. They dont live very long though and it used to upset me when they died. We always used to take ours on hols with us, self catering anyway because of the dogs. Used to have to sneak the rats in!
Yep, she really must have a friend - they're not animals that can be kept alone. Average lifespan for a pet shop rat is around 2 years, but my oldest is around 3 years old now, and still going strong (bit wobbly, but who wouldn't be at that age?)