My job is based out of ny but I only work there once a week the rest of the week I work in nj. All my taxes were withheld in ny I know that I have to pro-rate my taxes and get a refund from ny on 4/5th and pay it to nj and take a credit to nj from the 1/5th that I paid to ny. On the ny it203 form were it asks me for the amount that was withheld in ny should I write the full amount or just 1/5th ?

You will write the full amount that was withheld.

Agreed.