None of us in the house have had this happen to us, but the first response from my partner when I asked about your post is
"it sounds like the frame is too big for her"
He also suggests shifting your seat further forward and put a longer stem on the front to shift your centre of gravity further forward.
Good luck
EDITED: My partner says he has had the front wheel lift on a climb before, but its on a REALLY steep climb, and only when he is seated.
(REALLY steep being a 15% or more climb)