Event Promotion, volunteers, and website managmeent are some of your biggest tasks.  A good sponsor letter will help you get some donations ahead of time.  Since you only need to save $ for promotion for the next year, find a charity to benefit you that might also benefit from the exposure.

The Duathlon I co-chair is the Columbus Duathlon www.columbusduathlon.com 

If the charity you link up with is a Non-profit, google has TONS of tools available to you through google grants and google checkout among others.  I set up my website on blogger but they do have some others.  Active does a good job with their website for registration and stuff.

Timing is a difficult item, and it depends upon the size of your race.  A small race of less than 200 people, you'll likely find bibs and/or markers to be the best way to identify runners and just write the information down as they cross.  Bigger than that and you better be ready with a chip timing solution.

questions- email me at columbusduathlon@gmail.com

I attach a sample donor letter for reference...