Can I report her to immigration?

4 years ago I married a girl from Colombia, She came here 2 years ago. She has no her green card. But 5 months ago she left the house ." for a better life". Thank God we had no children... What can I do? Where can I go to report her for taking advantage of the system and now wants to get married and give a green card to another guy? Is she suppossed to show that she was with me during some time in order to have a final green card? please respond.