Taxes on lottery winnings

I recently won 1,000 dollars via the lottery in the state of NJ. I understand as long as  i provide a social security number to the Lottery Bureau they will take 25% out before they even cut a check.

How much more wil lit get taxed come the end of the year? Do they tax the 750 or the full 1000 at the end of the year if it is indeed taxed again?

Is the tax rate determined by my entire income bracket? If I stay in the same tax bracket, is there additional taxes due to the lottery?