Ok, Kaya was like this and I certainly wasn't ready to give up. You don't need to give up BFing or co-sleeping or let her CIO, what you need to do is get a good bedtime routine going - bath, teeth, story, feed. Once you've been doing it for a week or two, change the order of the story and the feed, so it's feed then story. If she falls asleep before the story, fair enough, but try to stop the feed when she's drowsy. Once she's going down ok with this, you can move the feed to before the bath. This is what worked for us.
Another method I've heard good things about is to feed until she's almost asleep and then gently remove the breast and put your finger under her chin, if she cries give her back the breast but keep trying to remove it with this method. The idea is that she learns to fall asleep on her own.
You also need to decide if you actually do need to get her to stop. If it aint broke why fix it? If it gets her to sleep quickly and easily why make things difficult for yourself? People often say 'oh don't feed them to sleep' with BF babies but most bottle fed babies are fed to sleep as well.
Sometimes I wish Kaya would just fall asleep with a feed, but tbh she's outgrown it. And that's the other thing, they do outgrow it, surprisingly quickly at times. A year or two from now and you'll be wishing you could just plug her in and get her to sleep, as you chase her back up the stairs for the 50th time! lol!