You might look at Hope College, in Holland, Michigan: http://www.hope.edu/index.html. About 10% of the students are psychology majors, which suggests a robust psychology department.
Also, Calvin College, in Grand Rapids, Michigan: http://www.calvin.edu/. About 5% of the students are psychology majors, and the psychology department appears to be decently sized for a LAC.
Neither of these schools are Catholic in ownership or affiliation (Hope is affiliated with the Reformed Church in America; Calvin is affiliated with the Christian Reformed Church), but both have a religious “flavor” to them.