One of the great things about the Catholic Church is that her teachings can be found in depth in written form open to the public. (Unfortunately, this cannot be said of almost all evangelical churches.) Let us examine the actual teaching of the Catholic Church to see if it falls prey to this charge.
The doctrine of the Immaculate Conception was declared dogma in an Apostolic Constitution issued by Pope Pius IX on December 8, 1854 entitled Ineffabilis Deus. He defines the dogma as follows:
"the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved free from all stain of original sin"
Let's unpack this a bit:
The Church teaches that Mary was conceived without Original sin by God's grace ("by a singular grace and privilege granted by Almighty God").
The stain of Original sin is passed on to every human through their parents. So in her very conception, Mary was set to receive the stain of Original sin. But God, in view of the cross, intervened and prevented her from receiving it. From this, Pope Pius IX concludes in another part of the same writing, "hence, she was redeemed in a manner more sublime."
The charge that, in maintaining the Immaculate Conception, the Church teaches that Mary did not have a savior is simply false. Mary was redeemed by God's grace through Jesus. Mary rightly praises God as her Savior.
Mary was saved, too.