Do some research into
HIIT for your cardio training, it works quicker than pottering around on a treadmill for 30 -45 mins and on average you only do 20 mins, you will prolly have to work up to this.
And yea i always thought you would get abs from doing heaps of sit ups, ive been particular skinny all my life, but never had abs, but ive recently cracked down on what i eat and only three weeks into it ive noticed my stomach becoming firmer