This my cardio routine, but it has a lot of running.
Monday - 5 Miles long run
Tues - Sprinting
Wed - Swim 1 mile
Thurs - 5 Miles long run
Fri - Swim 1 mile
Sat - Sprinting
Sun - Rest
If you don't like running then there are loads of other options.
Swimming, rowing, bike, cross trainers, skipping, fast walking, bag/pad work. Depends what you wanna do. Treadmill is by far the most boring excercise, but it works