A surprise, is meant to be a surprise. So, NO hints. Just surprise her all at once. TRUST me, girls love it. We really DO get SURPRISED.
I want to surprise my girlfriend, should I give a hint or tell her i have a surprise for her, so the anticipation builds or surprise her all at once?
Keep that a secret untill you give the gift to her, keep her guessing.
I think you should give her a hint at first, just to see how you think she would react, but don't give to much away, then just out of the blue surprise her.