I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear that this happened.
A restraining order typically is for when someone is threatening you or your family with immediate, physical harm, and you have reason to believe they are willing and able to carry it out. This person has no way of causing you a physical injury while you're in the Philippines or Washington state, if she's in Alberta, Canada. You can, however, block her on social media and ask your wife to do the same, so she cannot post things on your wall for your friends to see. You may also want to look into changing your account so people can't write on your wall or tag you in posts without you approving the message.
As for the post itself, it is defamation of character to tell people that you're having an affair when you're not. You would have to bring the people who saw the post into court with you to testify about what they read - a written statement is hearsay, because it can't be cross-examined (even if they signed under oath, a judge can't base the entire case on hearsay). The bigger problem, though, is where to sue. You can file a lawsuit in Calgary, but you cannot ask a judge to order her to pay your costs of traveling there. You can sue her in Washington, but it will be extremely time consuming and expensive to collect a judgment unless she owns property or has bank accounts in Washington. Since the post was only up for a few minutes before being removed, unless she posted it again, it's possible that you'd be spending a lot of time and money trying to collect just a few hundred dollars. There are valid reason for doing this, but I just want you to know that you might wind up not getting money from her.
What she's doing is considered cyber-stalking, which is illegal under Washington law. RCW 9.61.260. You can file a police report, but since the Washington police can't arrest someone in Canada, you may have more luck with the Internet Crime Complaint Center.
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