Hey
You will never have complete muscle definition until all the fat is gone 1st, so for the 1st month on so, you should be doing more cardio than resistance training. Also, remember to mix your workouts up a bit as your body gets used to doing the same work out all then time, and as a result, you hit a weight loss plateau.
Circuit training is a brilliant way of keeping your body guessing and to lose weight fast.
Also, toning trainers are brilliant! I love my shape ups, and really have noticed a difference in how toned I am. They are cheap on ebay, and a brilliant investment. If you wear these while doing your exercises, you are working different muscles that you normally wouldn't.