The card idea is nice. I'm one who suggested you give her time, but if you really want to send the card, can you just mail it? That way, she will get it and read it in her own time without you standing there waiting for a reaction. After sending the card, I'd just not contact her again and leave the ball in her court. I know that not knowing what a person is thinking can drive you nuts, but, in this instance, if you want to preserve this friendship, I would suggest that you allow her to deal with this in her own way.