What should I do if my female boss is stealing, and this is harming me because I am present with her in the workplace? What is the ruling on informing her superior about this?

If you ascertain that she is stealing, then forbid her and remind her of the seriousness of theft and transgression against people's property. If she does not respond, then inform someone who can restrain her and hold her accountable for that; because the Prophet, peace and blessings be upon him, said: "Whoever among you sees an evil, let him change it with his hand; if he cannot, then with his tongue; if he cannot, then with his heart—and that is the weakest of faith."