Very few. You're looking at basically having to buy some program like those offered at lostpassword.com and hope it can break the encryption. And not to rub salt in the wound, but when you encrypt something using EFS, it does pop up with a message telling you to back up that encryption key file, because without it, you will be unable to access the files. Somewhere along the line you chose to ignore that warning, and so now here you are.
I don't say it to chastise so much as to help you make sure to learn the valuable lesson from this experience. That is the difference between this being a one time event or simply the first of many.