salvador ramires families researches

tryingto find earlier records for salvador ramires or ramirez who had married a woman by the name of pasquala melendes . family search has marriage record 06 February 1681 • San Francisco,Villa De Reyes,San Luis Potosi,Mexico .. their daughter known as rita franca ramires married nicolas de la rosa and had several children including my maria bernarda de jesus de la rosa and places them in or around san luis potosi mexico where can i go or whom i can talk to about the earlier records for these family as i have hit some brick walls and would like to know more about their histories? i have attached the film number in family search records as follows: Film Number 004806532 or is there any books or anything of the relevance i can buy?