Your first step should be to contact an attorney in the county where the charge originated. Different counties handle this scenario in different ways. For example, Wake County would force you to plead guilty before you could start the process of getting back your license. Other counties may dismiss it based on how the limitations statute was written back then. Either way, you need an experienced DWI attorney FROM THAT COUNTY...
Basically you should not have even been drinking. You need an experienced DWI attorney - there's really no way around it. Best of luck.