When you say "no attempts to contact the mother have been successful", do you mean that she is just refusing to pick-up the phone/return your messages/reply to your emails or do you mean that you have been unable to confirm her location/contact information? If it is the latter (you aren't 100% sure how to contact her), then you may want to focus on getting someone to track her down for you first -- a P.I. or person locator service, for example. As a practical matter, it does you no good to get a court order ordering the enforcement of a court order if she can't be found to enforce it on.
If and when you know where she and the child reside (you will need this information to serve her with anything, anyway), then I would suggest as your next step that you have an attorney assist you in communicating with this person. While she may not return your calls, she is far more likely to respond to a letter from an attorney. If the attorney can express to her that you are very much interested in working with the mother to insure that your re-introduction into the child's life is done with appropriate amount of gradual, safe, structured visits as may be needed (rather than just simply attempting to assert some visitation schedule from 7 or more years ago), then perhaps she would be willing to listen and consider negotiating a more appropriate current arrangement without the need for judicial intervention.
Given your record and the lack of contact with the child, a negotiated work-out with the other parent would probably be your best option. If that does not work, then you will need to go back to court and either petition for enforcement of the current order or for a modification of custody/visitation.
This response does not create an attorney-client relationship and is intended for general information purposes only.