The validation code for credit cards is only 3 digits unless it is a certain type of American Express card. What type of card is it? http://en.wikipedia.org/wiki/Credit_card_number
In any event, you can purchase a retail copy of OneCare and use the PIN/Key from inside the box to renew the subscription. If OneCare has already expired or is about to expire, you are still protected for at least a week or so after expiration, though you will not be able to perform any manual tasks or make changes to OneCare when it drops into expired mode.
-steve