Don't feel heelish...people make mistakes.

Just send the card and apologize for it’s timing.

I think the suggestion to send a Christmas card. when you see her give her your condolences. Grief is something that is an ongoing process. After the funeral it seems everyone disappears and no one checks on you ,at least that's been my experience. I'm sure she would appreciate your condolences even if time has passed.

Just send the card you have, unless it's dated or something like that. Grief is around for a while so getting a card later might actually be a good thing...people are still thinking of her and the pain she's going through. The holiday's are particularly hard if you've lost someone recently.

Send the card that you have, - there's no statute of limitations on such things.

It's the thought - right ?

Send the card with no further explanation nor apology.

I wouldn't link Christmas too it. Your sentiments and regards are enough. Otherwise it might appear you are trying to kill two birds with one note.

Best thing is probably hand deliver the original and verbally explain the mix up.

There's no real need for a new card. I do not recommend sending her a note in her Christmas card as it could possibly make her more emotional (mainly due to it being Christmas). If you are going to take any future action then I suggest a face to face consolation. People need that kind of interaction when it comes to an emotional matter such as this.

However due to the nature of your relationship I would not advise you speak to her about this matter. It is more of a personal matter and she has to go through it either alone or with friends who are closer to her than you (No offense intended).

As we all know. You are the one who needs to make the decision in the end. Do what you believe is right, that way you won't have any regrets. If you feel that she will benefit from you consoling her then do so.

Also this is coming from a 19 year old man so I understand it you disregard this comment completely as I have insufficient experience in dealing with events such as these.

I agree with @evidentialist
Just the right answer.

I see no reason to make an apology or excuses. I know from experience that there is a flurry of sympathy at the time of a death but then people fade away and the bereaved is left to "deal with it." You should just send a hand written letter of sympathy acknowledging that your colleague is still probably hurting and offer your friendship and an ear to listen to anything she has to say and offer to help in any way you can. Maybe invite her to dinner just to talk.

You don't sound very close to her. I mean, not close at all. Why would you even worry about it? I wouldn't send anything, and just let it go.

Condolences should not be in company with Christmas greeting or any other festive notice. What I would do is send another sympathy/condolence card with a simple explanation, not an apology as such. Two days later, send the Christmas card so that the two are separate and distinct.