I would actually add some resistance training to you regimen for weight loss. Cardio is good, but resistance training just as good. A combination of the two cannot be beat. Also you might want to look into interval training. For example, on your route sprint as hard as you can for 30-60 seconds. You want to sprint long enough to where you're working hard but not so hard that you're completely gassed. Then do a light jog for roughly twice the time you sprinted. This will allow you to recover. Then repeat until your total distance is covered. We call these 60-120s and they work really well to help us train for the two mile portion of the PT test. I'm an active duty nurse in the Army but I am stationed at a hospital so I spend a lot of hours indoors instead of out in the field training so I have to work extra hard at PT for a good test score.
I think if you ran 3 days a week, and alternate those with 2 or 3 days of a full body multi-joint lifting program, you would do quite well and bust through your plateau.