You should be able to run 2-3 miles with good sprint training. The problem is knowing how to pace yourself if you don't practice.
Also when doing sprints do you run only a certain distance or do you run as fast and as far as you can? The later will increase cardio more.
Do you have to do the typical 1.5 mile run? If so just go out and do a practice run or two. Should only take about 15 mins.