Greek source please.
This has been covered so many times and shown not to mean this.
The salutation of the angel Gabriel -- chaire kecharitomene , Hail, full of grace ( Luke 1:28 ) indicates a unique abundance of grace, a supernatural, godlike state of soul, which finds its explanation only in the Immaculate Conception of Mary. But the term kecharitomene (full of grace ) serves only as an illustration, not as a proof of the dogma. http://www.catholic.org/encyclopedia/view.php?id=6056
This is a bad translation. More properly the greek is translated as "Greetings, you favored with grace."
It is not a title as catholics have taken it to be.