After 40 years as president of Villa Maria College, Sister Marcella Marie Garus will step down in June.  The college announced her retirement Wednesday and said a formal search for its next president will begin in the coming months.  Garus, a member of the Congregation of the Sisters of St. Felix of Cantalice, served for 10 years as business administrator at the college on Pine Ridge Road, before taking over as its third president in 1978 making her one of the longest-serving presidents in Western New York.