I am sorry that you fell victim to this all too common Craigslist / Western Union Scam. I regret to say that your money is gone, and its very unlikely that it will be recovered. A police report alone is not going to protect you from identity theft.
If you gave the scammers information like your social security number or other personally identifying information, then you should be concerned about possible identity theft. There is lots of information on the internet about protecting your self against identity theft that you can find.
I am an attorney who is only licensed in the State of Florida. My answer is general legal advice based upon what I perceive your question to be, and should not be relied upon because every person's facts and circumstances are unique, and because specific laws vary from state to state. To completely evaluate a legal issue requires reviewing and evaluating all relevant facts, applicable laws and other information. My answer does not create an attorney-client relationship, and offered for informational purposes only.
To add to my colleague's advice, you're not going to ever get your money back, and this is an expensive lesson in why it's unwise to buy a used car sight unseen and wire money to someone.
You can "freeze" your credit, so that no one, including you until you un-freeze your credit, can open an account in your name. Please see the FTC link below
As for protecting others, that's why you should call the police and file a report, and also check with your state's Attorney General to see if they're investigating these particular scammers.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.
While I agree with my colleagues, I would still file the police report and you might also contact the State Attorney General's office. If they get enough complaints like this, they may go after these thieves.
*** LEGAL DISCLAIMER I am licensed to practice law in the State of Michigan and have offices in Wayne and Ingham Counties. My practice is focused in the areas of estate planning and probate administration. I am ethically required to state that the above answer does not create an attorney/client relationship. These responses should be considered general legal education and are intended to provide general information about the question asked. Frequently, the question does not include important facts that, if known, could significantly change the answer. Information provided on this site should not be used as a substitute for competent legal advice from a licensed attorney that practices in your state. The law changes frequently and varies from state to state. If I refer to your state's laws, you should not rely on what I say; I just did a quick Internet search and found something that looked relevant that I hoped you would find helpful. You should verify and confirm any information provided with an attorney licensed in your state.