Oh ouch...How long has this been happening? Is it possible your supply could have dipped because of AF being due, or pregnancy?
After 1yr as long as LO is eating a good range of fat, protein and calcium rich foods (cheese, yoghurt etc.) they don't need cows milk, it's just an easy way to get these things in to them if your LO likes milk. If you want added vitamins you could use formula instead of cows milk. If LO won't drink any kind of milk after weaning from the breast you'll just have to make sure there is more milk mixed in to food, or cheese and yoghurt based foods.
I didn't change any bfs to bottles as I did continue to bf after 1yr but I did change some bf feeds to snacks as she was so distracted she was on and off all the time. I chose which ones she was already distracted for and made sure there were loads of distractions around - i.e out at a play centre or park and then just offered the snack (cheese square and some fruit) around the time she usually fed. She ate it and didn't miss the bf at all. I'm sure you can use the same technique for switching to formula bottles or cows milk after 1yr.
You may find that his feeding behaviour changes again over the next 3 months though and you might not want to switch. He'll probably drop a good couple of feeds between now and then too so you may not be as sore as you are now!