Hi Andrea,
The type and intensity of exercise you’re doing will count, as will your calorie intake. A dietician will help you determine how many calories you are currently taking in, how many you are burning, and how many you need to be expending to create a calorie deficit.
When it comes to exercise, the minimum requirement is no less than 60 minutes of cardio a week, preferably with intervals of high intensity (ie. sprints). Strength training is crucial for weight loss, and a minimum of 2-3 sessions of 30 minutes a week is required. Each workout should have 5-7 different exercises, where you perform 3 sets of 10-15 reps for each exercise. Your weights should be heavy enough that you struggle to perform the last few reps of your last set. If you need supervision and don’t have a budget for a gym contract, invest in a fitness DVD, where the trainers will run you throuhg well-structured and effective classes.