Hi Kari - I agree with everything Lisa said (but then, she's my hero

), and will add my own experience for you. I was exactly your weight when I started the 'Couch To 5K' Programme the first week in June '07. I had to tweak some weeks a little bit - ran an extra day rather than move on and such. And trust me, I was SO NOT FIT. It was hard - even running the first 60 seconds. BUT - totally doable
I finished the programme in exactly nine weeks, and am currently building up to running 10K - I now run at least 4 miles, three or four times a week. I LOVE to run, and I was never athletic, never DREAMED I would be a runner. I started training outside, but I have a treadmill now, and have a love affair with it

At least once a week I do hill work, just to shake that cardio up a little.
Adding the weights is an excellent idea, but maybe don't add them at the same time you start running - why not run a month and then add the weights? I can only speak from my own experience, but the C25K programme dominated my life -

!
Good luck, and keep posting in the Cool Runners forum so we know how you are getting on!!
Heather