Hello Clare:
You basically have proven to yourself that you are able to quit. You have also proven to yourself how easy it is to relapse. Your idea of maybe needing to read more is right on the money. Not that you need to read more on how to quit--you know how to do this. What you need to focus your attention on is how to stay off. We have made a lot of information available for all on this very topic.
I am going to attach all of our relapse prevention article links below. Every one of these articles will give you the understanding of what went wrong with every one of your past failed quits. All you will need to do is to read the articles all the way through to the last four words on any of them. If you make it all the way to the end they will all make it abundantly clear that all you will need to do to make this quits last from January 30, 2005 to the rest of your likely extended and healthier life is to make and stick to a personal commitment to never take another puff.
Joel