I'm no expert on intolerances, but I would suggest that if you are losing weight yourself because you've cut back your diet so much, the easiest thing to try is to count calories and make sure that you're getting enough food for yourself, plus breastfeeding, every day, no matter what. Your milk might be poor quality if you're malnourished yourself.
Are you eating plenty of meat? Lamb is supposed to be the most allergy-free meat - maybe you could get a couple of lamb roasts while they're on sale for Easter.
As to the bottle, my baby was so, so resistant and finally took on when I left the house before he woke up in the morning. DH was the only one home, and he only had a bottle to offer, and I was so surprised when he called me and said that he took the whole thing! Of course you don't want to be cruel and starve a baby who's already struggling with weight gain, but go out one morning and see what happens.
I've also read that some desperate mamas go on a diet where they only eat a few very safe foods for a week or two - I think I read it in a book by Dr. Sears, and I can look it up for you if you're interested. Then if that still doesn't solve the problem, you know that modifying your own diet isn't going to work. And if it does solve the problem, you can slowly add things back in.
Also, if she's not gaining enough, you might want to go back to more frequent feedings even if it throws off her routine.
