If I may I'd like to tell you what worked for me, and perhaps it may be of some use to you. I smoked on and off for 11 years or so, tried quitting many times, once for 20 months, another time for over a year, but my willpower would always end up running out and I'd be back at square one. Then I heard on a different Buddhist discussion forum about people who had quit using a method by a man named Alan Carr, I believe, and if I remember the name of the book it was "The easy way to stop smoking", or something along those lines. I never did read the book, but the method from what I understood was to be extremely mindful while smoking and ask just what it was you enjoyed about having a cigarette. Was it the taste? The feeling of the smoke in the lungs? etc., etc. Anyway, it didn't take me long to realize that I didn't enjoy smoking at all, and that the only reason I did it was to get relief from the nicotine craving. This was quite a revelation and it didn't take long until I was just fed up with smoking and had little trouble quitting, and whenever the thought about having a cigarette arose I'd think about just how awful smoking was in those final days because I really wasn't enjoying it. Willpower just didn't cut it for me, I'd always be suppressing craving, but this method quickly and easily killed my desire for a cigarette, and this October or November it will be 5 years since I quit, which for me is a major accomplishment. Anyway, just wanted to share, and wish you luck with quitting your addiction. You can do it!
"The heart of the path is quite easy. There’s no need to explain anything at length. Let go of love and hate and let things be. That’s all that I do in my own practice." - Ajahn Chah