As the years progressed, St. John Separate School was unable to accommodate the ever-increasing number of students. In 1957, the school board decided to build another school on O'Neill Drive. St. Augustin was opened on March 1, 1958, and was prepared to provide instruction in both official languages. However, when classes were set to begin in September, the board decided that the schools would function better if one were strictly English and the other French. With that, St. John became an English school while St. Augustin served as the French school. Bussing was then provided to both schools for all students.
Student populations continued to rise and in 1961, a new four-room annex was built beside St. John School. The building was initially called St. Pius X, but was later renamed St. John Annex. By 1965, two more classrooms and a kindergarten class was added to the Annex and in 1969, a library, a gymnasium, and four new classrooms were constructed. Through these additions, the Annex was joined to the school.
As with St. John School, St. Augustin was also in need of additional space. In 1964, two new classrooms were built over top of the gymnasium and in 1967, four more classes and a new library were constructed.
Enrollment in the separate schools reached its high point in the mid-1970's. St. John's population had reached 625 pupils while St. Augustin was educating 450.
Today, St. John Separate School and École St-Augustin continue to serve the Catholic children of Garson.