Beat her to the ball and let your last defender play offense.

The opponent is taking her out of the play essentially.
She should be rebelling about her actual playing time versus her standing around time on the field.

Send you sweeper to mid court area to clean up long balls and send them back in. This goalie marker is probably one of the opponents weakest players and not a real threat. Use her lack of involvment in the game to penalize the opponent with you more effective play with one extra attacker.

Surely at 45 you can beat a weak woman player. You could also use her as a shield and after being hit several times she will balk at being used that way.