I can recommend Tanya Birri from
FeMale Funk Project, she's a really positive, supportive person with such great energy. She would love your idea and the school hosts events where you can practice getting rid of your stage nerves if you have them. She coaches a friend of mine and he's really made great progress in a short time although he's not one of those people with natural musical ability, so if you already have a good voice, it'll be a breeze. A course of five lessons comes in at CHF 450.-.
Sadly the website is only in German but feel free to PM me with any questions.