you'd better see a additional-hour coach directly.Don't go to driving school, it will cose you more. As after driving school, you still need to do more exercise from a additional-hour coach, otherwise you can't pass the road test.
I prefer driving school. It is more safe. The teacher have another brake to avoid dangers. Any way general people need about 20 hrs practice. Some need 40 hrs. I myself practice about 40 hrs to pass the road test.