You've done right ignoring her as you know that for narcissists their goal is to get attention and to convince others that they are correct and better than the rest.
It may me helpful although difficult at first to separate the person from the symptoms of her condition. If she is a true narcissist, she won't feel empathy or compassion even if you confront her or even if you tell her that you forgive her and you love her. Yet, what would be beneficial to you in the long run is to remain positive even in the face of adversary and pain and attacks on you that come from your own mother.
As you resist to feed into her scheme, she may eventually either give up or change her tactics. But, having resisted her once or twice, she on some level will know that you can resist her again.
Instead, focus on establishing contact with those people whom she tries to get to believe her and show them that this sort of behavior can be harmful. Instead of appearing angry towards her, let her see that you're neutral and sticking to your own inner persuasions. Behavior is purposeful and she has an agenda behind what she is doing. Most likely it is not necessarily to make you feel or look bad but rather to make herself look good and right.
You may also want to try to see her behavior as opportunistic towards you rather than being targeted on purpose. It is easier for her to direct her energy towards you whom she knows and is aware what makes you tic rather than a stranger who may not give any weight to her behavior.
Surround yourself with those who love and support you because even though she is your mom, she is just one person. It must be also an awful state of being for her to live doing this to her daughter whether she realizes it or not (as though she's thriving on your pain) Try to conquer her with kindness even when she is harmful. That way you show her that you're above her and for a narcissist, that would be hard to swallow.
You may decide that the help you give her comes from your inner being and goes to her being rather than her narcissistic ego. She is another person who had made mistakes in her life because of either inability to act differently or refusal to do so. Yet, you can decide that you do not want to fight fire with fire and remain true to yourself by helping someone in need (even if it is her- the person who's hurt you) After all, you realize that the way she acts is unhealthy and painful and would not want to return unkindness with the same because as a person you're learning how to evolve past that.
You can help her as needed and view her behavior objectively without personalizing it (even when she attacks you) With practice it is possible to feel differently towards her and pity rather than anger because she's given up the wonderful opportunity to have a good relationship with her child. You could connect with others for support through NAMI.org or meditate on what it would mean to you to help her even when she's to remain the same.