I think you should invest in a the book the No Cry Sleep Solution and also know that 13 months is not that unusual for a baby to still be waking up. She might look big to you now comparatively, but she's only been on this earth for a year and change! She does not know better. I would personally continue to get up and comfort my baby until she was 2 1/2 or so. Then I may consider CIO, under very strict parameters, but I never needed it.
IMO If you absolutely MUST do CIO, although I do not advise it generally.. you have to do it during nap-time first. Do not try it at night or in the middle of the night - it is too traumatic. And you absolutely must stop once the baby has become very upset. If she is shuddering/shaking, vomiting, the process (you go in every 2-5 minutes or so and rub the back) takes longer than 30 minutes, or the cry takes on a high-pitched ring to it I think you should stop and give up that method.
at 12:30 AM on Dec. 1, 2009