My mom did something similar.
She outed me to a friend of her's without my permission, so I was pretty miffed. Later I realized that she needed someone to talk to about what's going on and I wasn't out to many people at that time. I've also never met this friend and may never meet her. So, I forgave her but I told her that I wanted her to ask me before she told anyone else.
She also outed me to extended family later on, with my permission. So that was okay.

Though in your case, you told her not to and she still did. So, I get where you're coming from. However, what's done is done. You were probably going to come out to many of those family members anyways, so, I'd try to forgive her if you still want her in your life. I'd also talk with her and explain why what she did was wrong and how it made you feel, it might sink in.
Amy