A week. Breaking the binge/crash cycle is the hard part. The extreme craving that occurs after the crash begins to decrease after 3-4 days, so if the individual can get past that period of time, they are more likely to stay abstinent. Psychological treatments are really all we have, but can help if you stick with them. There are some medicines, especially topirimate (Topamax) which may help.
Depends... The answer to this question depends upon how long the person has been addicted; and the strength of their conviction to quit and stay 'clean'. Rehabilitation facilities/programs can be a huge helper her. Best of luck.