Are you sure that you received this message from facebook? Possible that it is the spam fishing only.

Otherwise you have to change the password for your email account registered with facebook! Do this quickly, and set the strong password.

Outlook .PST file data can be easily accessed even it is password protected. But if you have the antiviral solution, there should not be the problem. Take a look to Outlook add-ins, possible you will find something new there.