That's made plain at the end of the Rosary, when you finish by saying, "Let us pray. O God, who by the life, death and resurrection of thine only Son, our saviour, Jesus Christ, hath gained for us the fruits of everlasting life; grant that we, by meditating on the mysteries of the Holy Rosary, may imitate what they contain, and obtain what they promise, through the same Christ Our Lord, Amen."
You're not praying to Mary when you say the Rosary - the Hail Mary is a request for her help. And each 10 beads you are supposed to be meditating on an event in the life of Christ -- if you look up the 20 Mysteries (there are 4 sets of 5) you will see that all but 2 are incidents from the Life of Christ (other than the Assumption and Coronation of the Virgin at the very end -- which can be seen as the ultimate reward of a holy life.) The Our Father, the Glory Be, and the Fatima Prayer (after every 10 beads) are all directed to God - The Our Father to God the Father, the Fatima Prayer to Christ, and the Glory Be to the Trinity.
You're not praying to Mary any more than you're praying to your Sunday School classmates when you ask them to pray for you. "Pray for us sinners . . . "
O my Jesus, forgive us our sins, save us from the fires of hell and lead all souls to heaven, especially those most in need of Thy mercy.