You create a new Power of Attorney revocation document specifically revoking her authority and have it notarized. Take it the bank and also submit copies to your credit bureaus. Explain what occurred to the credit bureaus if this has impacted your credit and report her to the police. She committed a crime and depending on the amount this person took from you, she may have committed a felony. The prosecutor should push for restitution as part of the charges and sentencing.