The real key to losing weight is diet and workout (obviously). And what people don't realize is that diet is actually about 50% of it. Here is what you really need to do if you want to lose weight, as it will kick your metabolism up and burn the most calories:

Eat 5-6 smaller meals a day instead of 3 big ones.
Remove excess sugar, salt, and fats from your diet, and switch to healthy fats.
Workout on a cycle of 3-4 times per week, with one workout day as a recovery day (just light cardio with carbs and protein to refuel).

I actually don't need to lose weight at all (only 150 lbs of pure muscle right now lol), but the diet I just described will cut out the bad and boost your good weight. So you may not lose much weight overall, but you will lose fat, inches, etc. and gain good muscle. I actually have a PDF file that goes into great detail all the foods to eat/omit, the diet plan and what to eat for each meal, the workout plan, etc.

I've lost 2-3 inches, 5-10 fat lbs, and gained back 5 lbs of lean muscle in just 20 days on this plan.

EDIT: Saw you don't like running on the treadmill. Try the eliptical machine. It is just as good for full body cardio workouts and is lower impact so it is softer on your joints and won't hurt as much during the workout. The days after is another story, though ;)

What nightsurge said.

Also, I wanted to say that you should never eat less calories than your Resting Metabolic Rate (the number of calories your body burns if you do nothing for a day). If you do your metabolism will slow down and your body will enter a "survival mode" and it will hold on to anything you eat once you start eating normally again.

It's always the same, eat less calories and/or burn more. For about every 7000 calories that you burn more than you consume, you'll lose about 1kg. Your results so far almost perfectly match those numbers:
15 pounds = 7,5kg = 7,5 * 7000 calories = 52500 calories
3 months = 90 days
52500 / 90 = 583 calories per day

That's very close to the 2000-1500=500 calories that you said you are currently eating less per day. If you want to loose weight even faster, eat even less or burn more calories.
I'd personally focus on eating less though. In my opinion it's much easier not to eat 100 calories than to burn 100 calories, especially for people who usually don't do much sports.

But why do you want to loose weight faster anyway? 15 pounds in 3 months sounds like a very good strategy to me. As far as I know, losing weight very fast usually comes with certain disadvantages, and reducing one's weight slowly but constantly is considered the best way anyway.

I recently lost about 10kg of weight at a similar speed and found this speed to be a very nice compromise: Less calories, but not so much less that I was actually feeling hunger. I switched to diet drinks, stopped eating shit too late in the evenings, and TRIED not to eat when I was not clearly feeling hunger. It was surprisingly easy, I didn't even think of me as making a diet.

Oh, and one more tiny tip from me: Don't weight yourself too often. I always laugh at my girlfriend when she once again tells me enthusiastically that she's lost two pounds in just one day even though she did nothing special, or when she is sadly teling me that she gained a pound since yesterday even though she ate less than usual. Real weight loss/gain doesn't work that fast, she lost the 2 pounds probably by simply going to the toilet...

i eat carbohydrates only in the morning, protein only in the evening, mixed for lunch.

i just finished running 2 and a half miles.

Substituting unhealthy drinks like soda and stuff like that with water helps a lot since you'll just pee it out in the end and it's also good for your kidneys =)