A.S.
I have a different view than many on this, being the child in a similar situation I would say for the sake of the child don't make this a big deal. Hide your true feelings about this woman and see how your daughter handles meeting her. 6 months is a guideline for parents but honestly as a five year old who met the other woman I can't even remember how many days, months or weeks passed before my Dad introduced her to us and frankly I don't care now.
What I can tell you is the right now you hurt and are in pain and you need to heal from that so get some professional help for you and your daughter's sake. It may seem like the "other" woman is awful right now and she may or may not be...time will tell. However your resentment of her will only hurt you and your daughter--remember this is her father not her ex-husband so he means something different to her and your pain is not the same as hers.
It's 28 years later now for me and I love my mom and my step-mom (the other woman) very much and am extremely happy to have them both in my life because they fill different roles and needs for me. However my mom never figured out how to heal and her snide comments have strained our relationship because what happened between her and my dad is between them...not me. Besides both of my parents are much happier now that they were when they were together. It's not right what they did but good people make mistakes. The only person you can control is yourself so good luck and I am sorry for your pain.