How do you do an internal citation of a quote from another person, found found a reference site?

Kind of confusing, I know. For my paper we had to choose our references before the paper, and once we had chosen our sites, we were not able to add/remove any. I want to use a direct quote from a site in the paper, but it is a quote from a person other than the author of the site. How would I cite that (MLA style)?