xiaozhu

As others said, IMMIDIATELY report to USCIS to PROTECT YOU before she files claims to against you, or comes back to you for marriage after she realizes the consequences of her running away. I heard some stories that the women file claims (like men's abuse claims) to put men into jails/trails, then get green card automatically.
Also by filing report to USCIS, you will be saved if you meet a right one oversea and want to file K1 or CR1/IR1 again in the future.
Also by filing report to USCIS, you also are doing a right thing to protect others who would possibly be hurt by her in the future, and stand up for justice.
You are lucky that you did not marry her. Otherwise, you will be responsible for all bills from her such as what you worry about.

This thread is probably the longest one I ever see. And Darnell is great patient and kind enough to all questions.
Chris, you claim your poor English but all of your writing is well-done. So please study the process first http://travel.state.gov/visa/visa_5162.html and then make questions, instead of taking Darnell as a "handy attorney".

It seems you will live with it until real trouble knocks your door instead of taking actions now to prevent the trouble. It likes your house roof is broken but you do not want to fix it till a rain day. It does not make a lot of sense to me. Maybe you have untold story. Good luck.

China does not allow double citizenships. When she becomes USC, only US passport for her. When she wants to visit China, she will need a visa.