Looking for my half sister

I'm sorry, but I don't have much information to go on. I have a half sister who may be in her 50's. She may have been born in or near Brainerd, MN. Her birth mom's name is Dorothy Weaver, which later became Dorothy Aanerud. Does anyone know where I can look to attempt to find her? Knowledge of her was kept hidden from me until I overheard my mom talking about her one day. My mom doesn't talk about her much and I don't dare ask my mom too many questions. She doesn't know that I exist and that I'm looking for her. Cdumpprope