How long does campral take to work and get rid of my habit?

Be patient. Campral will help with some issues related to stopping drinking, it helps calm the brain that becomes overly excited from alcohol. So it can help you and your brain be "calmer". Though Campral alone is not a cure to stop your habit. It must be used with other forms of support such as counseling or aa meetings. What it does is make those things more effective early in your sobriety.
Doesnt get rid of it. Acamprosate works by reducing a toxic substance in the brain (glutamate) which accumulates in chronic heavy drinkers. Glutamate is partly why people who quit drinking stay very anxious and jumpy, and Campral can reduce this. However, you need counseling and changes in the way you live your life to "rid" yourself of the habit, and that is more important than the campral. It work quickly.