I also met people like that, Elle (both in AA meetings, although I've been to only a few, and just in life). I would cut the conversation nicely and politely short when you run into her at meetings. If she asks to go for coffee, say you already have plans and maybe say what so that she does not feel like there is suddenly no communication. If she does not recognize your trying to keep distance several times, I would be direct and tell her you are at a stage where you would like to focus on you and activities you enjoy more. If you feel really bad about keeping her at arm's length, maybe go for a coffee with her sometimes and listen for a limited amount of time.