Finding solar panel costs

Right now I want to find a way to get solar panels for our green schoolhouse. I guess the first step is to find a contractor who can help us with all the paperwork involved in installing a solar powered system. Before that, I want to find out what cost range we're looking at, and before that we have to figure out our energy usage at Howard Street. Of course to do that, we have to get "Watts" up things to measure the our usage. I guess we're doing it one step at a time.