Any more progress? I would suggest you ask her to go out again alone or with a girl and see what happens. Have her model sexy cloths for you and pick the outfit you want her to wear. Maybe ask if she will wear a dress or skirt and no panties?
Take her to a bar or casino bar, dress her sexy, let her go in alone. She flirts and tells guys she is waiting for a work friend.
You come in 20-30 min later as the work friend.
See how that goes the first time, then build up to more for her. Even let her go out alone some.