Q: Can I file a complaint if I am a citizen of the United States but have been victimized by an individual or company outside of the United States?
If one of the two parties involved is located within the United States, please feel free to file a complaint.
From http://www.ic3.gov/about/default.aspx
The IC3 gives the victims of cyber crime a convenient and easy-to-use reporting mechanism that alerts authorities of suspected criminal or civil violations. For law enforcement and regulatory agencies at the federal, state, local, and international level, the IC3 provides a central referral mechanism for complaints involving Internet related crimes.
It looks like if IC3 can't do anything about it, they would refer the complaint to an organization that would be able to. If you live in the US, they will probably go to bat for you. If only the accused party lives in the US, they would probably investigate on the assumption that a fraudulent operation inside the US would also target US citizens in addition to violating the law.