The regular exercises
To begin loosing weight you need at least three fitness trainings per week. If you want to achieve the better result, then make exercises five times a week. But the workouts must be different by its directions and efforts.
Actually the best effect can be achieved as follows: three workouts per week with the weighting (dumbbells, weight-lifting exercises such as squatting, thrusts, push-ups, because they involve the great muscle groups).
The other two days load should be weaker and it must be with the other direction - aerobic, which burns calories. For this kind of fitness use a treadmill, exercise bike, jumping the rope, and step aerobics.
If you do not like aerobics, then in these two days you can choose (on the advice of a coach) two or three simple exercises and do them a great number of repetitions in up-tempo without any weighting. And you will get the same aerobic effect.
Remember, two classes per week only help to maintain muscles in the tone. If you are unable to go workouts in the gym, spend at least 10-15 minutes for exercises at home. Really it's better than doing nothing at all.