L.,
First of all, what was your purpose in working on this committee? Was it for the betterment of the school and therefore the students? If this was your sole purpose than I would say to you, "good job". To go beyond that scope is nothing more than trying to justify your personal feelings against someone you don't necessarily get along with. THATS LIFE!
It seems to me that you need to go back to kindergarten and review some of the life skills gleaned at that time. Examples being, play nice with one another, share, and say please and thank you.
L., its not about you or this woman. It seems to me that you have lost sight of why you are even volunteering at all. I would expect you to work out the deals you did and put in the hours you did if it was truly for the benefit of your school and children. Somehow, based on your posting, I believe that you used this opportunity selfishly. If you did the work, as you say, why did you put her name on it as well? You have created your own negative situation and are now weighed down by the burden you created!
Remember, that it was your decision to do what you did. Did you express your feelings to your colleague? If not, then you can't go back now and confront her on something in the past. Some simple form of communication may have alleviated your perseverating at this point.
I am teacher myslef and while I appreciate the hard work and dedication of our parent/volunteers, they create some of the biggest headaches due to jealousy and petty arguments.
Let it go. It sounds like you did a great service for your school and kids. Be proud of that, be proud of job well done. Swallow your pride and vanity and get back to what is important... your kids!