Hey amanda,
well it is as you said, important to add variety to your programme, this prevents boredom & improves your fitness as your body will need to adpat and learn this new routine.
A few things that might keep you going is to get a "buddy" to run with you, this will make it more fun and provide you with more motivation. Even small notes of encouragement around your house or something that will remind you of your goals will also help.
Essentially you want to work your fitness at an appropriate intensity for at least 30 minutes a day (can be two lots of 15minutes), 3 to 5 days a week.
Things like sprints, jogging etc and mixing it up, even swimming or bike riding if you can.