I don't think you can wean as such when they are toddlers. I would start with the day bottles and switch then for sparkly new special milk cups and only allow milk in those during the day. You could keep her bedtime bottle until she adapts to the day cup and then switch the bedtime bottle. You may need to change the routine if she always has milk in the same place to break the association with that time/ place and the bottle.
I'll move you over to toddlers too!
Laura