Three months seems an eternity but this will fly by when you start to see results. With a longer period for weight loss a good way to loose weight is to not eat carbohydrate (starches like rice, pasta, bread, potatoes) in the evening. During your evening meal you could combine a protein with a salad or vegtables (not potatoes), for example chicken salad, fish with mediterranean vegtables or kebabs and salad. In addition you can have fruit to snack upon.
For lunch combine a moderate portion of carbohydrate (slice of bread or a fist size portion of pasta or rice) with a low fat protein. At breakfast you can eat a normal breakfast meal of cereal or toast.
By introducing this curfew you are having a lighter meal in the evening and eating carbohydrates in the day when you need more energy. As you have not omitted carbohydrate fully from your diet you will not be missing essential nutrients from you diet.
To lose up to 2 stone in three months you should also aim to introduce regular aerobic exercise into your routine.