I want to get married in Oaxaca, Mexico?

me and my husband (civil) want to get married through the Church in the Cathedral de Santo Domingo, in Oaxaca. I'm trying to find out information on who to contact, and how to find out all the information needed in order to book it. I know I have to have at least 6 months in advance, etc, but I cannot find out more information on weddings there. Any help? Money is not a burden, and i'm set on getting married there, it's gonna happen there. Thanx.