Wow, That's great news, Glad to hear everything is working as should. To do a Marathon, well it could be done.
My Cousin quit smoking (20yrs) and a year later she did a Marathon, and a Triathalon (sp?) couple years later. She hoping to go to the Greece for the 2009 Olympics
All you need is determination, and you can do alot of things.
It's shows that you have a lot to be quiting bad habits and are determined to live healthy. Right On!
Keep up the good work