I need some advice Please

I had my surgery on 7/22/08.....I started at 283#, I currently weigh 174.6 and am loving every minute of it. My dream/goal has been to do a race in my little home town and there is one on 8/3/09.  It is a 1.5 mile run, an eight mile bike ride, and another 1.5 mile run. I want to do this more than anything in the world, but, I am afraid I won;'t make it. I walk a mile and then run one mile 3 times per week and then I do a 3 mile bike ride 2 days per week, but, how do I increase it without going overboard, I can't afford a trainer, but, any advice would be appreciated.

Thanks!!!!!!!!!

Gradually start adding distance to your run.
The bike ride probably won't be a big deal for you.
Where you will most likely experience the most difficulty is the second run after the bike ride.  Your legs may not feel right. 
Have you tried going from a short ride to a run yet?  I would recommend you try that.  It's called a brick workout.

If you search for running programs you can find a lot of them on the web.
I liked the couch25k program when I first started.  Since you are already running, you can begin the program at the point where you are right now.

http://www.coolrunning.com/engine/2/2_3/181.shtml

Scott