Does this person still present a threat to you? Has there been any violations or contact for the past 4 years. You know what the court asked you when you were granted the order 4 years ago so are there any similar issues now?
It may be difficult to establish that you need the order extended if nothing has happened in four years. Also, nco are out of criminal cases at the court may be running out of jurisdiction. You may need to apply for a protection order. You should consult with a local attorney over why you still need an order 4 years later. That will give you your best chance of still being legally protected.
Go to Room 108 at the County City Building and tell them you want to renew your DV order. They will provide you with the needed forms and tell you how to go about serving the other person and the answer any other questions you have. The County will not contact you about an order that is about to expire. You also have to file before the order expires so be sure to go down to the County-City Building right away.