What can I do if I used a credit card without permission?

I’m a foreigner, used to be engaged to an American girl. Things didn't work out and she left me for someone rich, 6 months later. I used her father's credit card without his permission to apply for a US medical exam, $1400 dollars. I tried right away to cancel it but it is nonrefundable. I sent her a message to explain what happened and she said they returned them the money and that there might already have been consequences to my action. I used that same credit card before for a former exam but back then I paid her the money in cash when she came to my country. She took $2400 dollars in gold from me and said back then she'll sell it so that I can use the money for my exams but never returned it. I am still outside the US, how is this going to affect my visa and career in the US, and what should I do?