Deciding to work out again...

Over the last 3 months, I guess because I have changed how I eat... I have been losing weight. So I decided that I will start working out and help that along. I want to be able to run in a marathon eventually. Thats my new goal for myself. By next year summer time, I want to be able to run a marathon. Big goal for me yes... considering Im normally pretty darn lazy!
But at the same time I want to lose about 25 lbs. Since I havent run since track in sophomore year of high school... Im going to start with walk/run method and work my way up! Hopefully 3 weeks from now I can go 30mins running at a constant.... adding 5-10 mins a week until I can go for an hour.... and now that its nice outside, on my off days from running ill ride my bike.
On top of that I am going to alternate daily between Biggest loser boot camp and biggest Loser yoga....
we shall see where this leads me... Im excited though! Hopefully that will be enough motivation for me.