There are two possible scenarios here.
Either this is a scam that your daughter is not concerned in and knows nothing about, or otherwise she is a gambler.
Your post gave me the impression that your daughter had phoned you asking for a loan, so presumably this is not a scam.
If your daughter is already addicted to gambling, helping her out this time will not stop her from going on gambling.
If this is her first venture into gambling the amount she is now in debt might just scare her into stopping gambling, but unfortunately it is easier to say you want to stop whatever it is you are addicted to, than actually to do it.
In no circumstances should you tell her husband about this.
What you must do is to insist that your daughter tells him - if she cannot face the prospect, then you can offer to do so on her behalf, or to be present when she talks to her husband about this.
I realise this has been a dreadful shock to you and I am sure that by now you have realised that you cannot and should not betray your daughter's confidence.
To make sure that you only are helping her with the one payment, which in all conscience is a dreadfully large amount of money, phone your bank now, cancel your card, and ask them to move the balance in the account your card and other details pertained to into a new account.
Check whether the payment you authorised your daughter to make has been made and to whom.
Then get hold of your daughter and insist that you and she meet face to face to discuss this in all its details (except of course your new bank account no. and any other bank cards you may have.)
You are justified in asking her how long she has been gambling, which form it takes, and whether she owes more money than she has told you about.
You should also make it very clear to her that you neither will or can help her finaciallly again and that you need to know whether she intends getting professional help to deal with her addiction to gambling. And do not allow yourself to be persuaded that it was a one-off thing, nothing to worry about, and will not happen again.
These are standard answers any drug adict, gambler or alcoholic will give you, but unless and until they themselves wish to conquer their addiction, their promises are meaningless, as they are just not able to keep them.
If your daughter is addicted to gambling, I would suggest that you contact professional help for gamblers - they will have a help service for concerned relatives who need advice regarding how best to help the addicted person.