J.H.
Preschoolers and Kindergarteners are actually called Girl Scout "Dasies." Brownies are 1st and 2nd Grade. Try this website http://www.girlscoutsazeast.org/ and click on the link "Looking for a girl scout troop in the East Valley" on the right side, toward the bottom of page. It will allow you to send an email to the coordinator -- you tell her where you live, she'll give you the contact info.
Good luck.