I attend a parish named Immaculate Conception. Within the sanctuary, there is a statue of our Lady holding the child Jesus and a large painting of Mary behind the altar. I think the altar area should remain wholly dedicated to Christ. Am I wrong?
Your concerns are not without merit. While there are no rules absolutely forbidding images of the saints in the sanctuary, current norms and customs speak of the sanctuary area of the Church as emphasizing the altar, the ambo (pulpit), and the chair. There should also be, on or near the altar, a crucifix. Further, the tabernacle, in most parish settings, is usually in a prominent place, either within or very near the sanctuary (cf Built of Stones, #s 54,57,74-80).
That said, while images of Mary and the Saints in the central axis of the sanctuary are not common in modern Church design, it is not absolutely forbidden either. There may be some merit to have the patron of the parish Church, in your case Mary, prominently displayed (as many older churches do) somewhere near the front, presuming it does not overly dominate the sanctuary.
Perhaps a spiritual way to accept what you consider less than ideal, is to remember that we do gather with the saints at Mass. Scripture says We are surrounded by a great cloud of witnesses (Heb 12:1). There may also be benefit in recalling the description of the early Church at prayer: They all joined together constantly in prayer, along with the women and Mary the mother of Jesus (cf Acts 1:14).
Always remember that we pray with the saints, and they with us; we do not worship them.
"Building our Catholic faith one question at a time."