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.
The Catholic Church has so twisted scripture that it's unrecognisable. It's no wonder they tried so hard to keep scripture out of the hands of the masses.