The following is the same prayer being said during the Novena at the National Shrine of The Divine Mercy.
Father, You prepared the Virgin Mary to be the worthy mother of Your Son. You let her share beforehand in the salvation Christ would bring by His death, and kept her sinless from the first moment of her conception.
Help us by her prayers to live in Your presence without sin. We ask this through our Lord Jesus Christ, Your Son, Who lives and reigns with You and the Holy Spirit, one God, for ever and ever.
(NCCB, Sacramentary, December 8: Solemnity of the Immaculate Conception, (p. 752-753).