That's a fairly good cardio plan. Do you run continuously at 12 for 30 minutes or do you sorta alternate between lower speeds every 5 minutes or so to do a sorta high intensity low intensity thing?
I don't have a weighing scale where I'm currently staying but I've been trying to lose some weight since March/April. I ran on the treadmill several times a week, occasionally went swimming, and I went on a controlled diet plan [restricted refined carbs, high protein, high fibre]. I'm planning to start an abdominal crunch regime soon, too, in addition to my cardio plan since my legs are already fairly well-toned. For sexy-looking legs, remember to run on an incline!
While I think exercising is very important, what you eat [and don't eat] is equally important in trying to lose weight. Many of us just eat way too much. We eat and eat and eat as though we plough in farms and work hard labour, when we actually spend half the day chained to a desk.
Also, beware the refined carbs. And half the people I know don't drink nearly as enough water as they should be drinking. [Keyword here is "water", not "beverage", a silly assumption which many make. And no, you don't actually need 8 glasses a day, you just need enough for yourself.]
Exercising's great to increase your metabolic rate, and very important in keeping your heart healthy, but at the end of the day I think effective weight loss requires a two-pronged approach of exercising and controlling your food intake. I can't weigh myself here, but I know I've dropped two inches of waistline, and counting! Definitely feels good to be shopping for new jeans two sizes smaller.