Zea is correct, lots and lots of chlorine. You'll need to know your CYA level to determine your shock level. Raise the FC up to shock level and hold it there thru frequent (hourly if possible) chlorine additions until the FC holds overnight. This can and has taken weeks for some pools, depending on how bad the ammonia is and how frequently one can add chlorine.
You need an FAS-DPD chlorine test to know when you are done shocking. Use only liquid chlorine for this process.
(you can do a google search, bottom left corner, for other threads where Ammonia was the culprit)