Have her do 15minutes cardio (elliptical machine) warm up while you're already lifting your first set workout.
Then when she finish, have her workout next to you, explain that she would have to do more reps and sets than you do in able for her to attain muscle tone. Perhaps a plyometric exercises is best for her, have her do 12-15reps of all workout with very light weights as you move on to your workout. She can even do 2 sets of 15reps for every part of the body- Make sure you pay attention to her as well...Do your sets then while you rest, have her perform her workouts, watch her form and moves. Then if she wishes to join you for cardio at the end of the workout, she could do so- it will help her get firmer and tone.
I hope this helps. Good luck!