I could write a book about this I think.
1) As you've noticed from all the responses, it's very common. Some babies outgrow it by 6 months, most outgrow it by 12 months, and a few never do. I wouldn't try again until 6 months, because it's unlikely she'll outgrow it much before that anyway. If she's still allergic at 6 months, wait to try again until 12 months. In the meantime, Rice Dream milk (rice milk) is a good option for baking and for on cereal (I wouldn't drink a glass of it though); and Earth Balance butter is good. Veggie Slices cheese is ok. These are all sold at most Giant Eagles (I notice you're in the pittsburgh area). If you want more tips, feel free to message me. I've been doing it for 6 months now and my shopping list is pretty good now - I found frozen rolls without milk, cookies, etc. My little one hasn't shown any reaction to soy, but I try not to overdo the soy in my diet, just in case (so, for example, I think the butter I mentioned is soy, but the milk isn't).
2) Nutramigen by Enfamil and Alumintum by Similac are both made without dairy or soy. They are very expensive, thank goodness you (and I) don't have to use them full-time. But in a pinch, they work. I use the Nutramigen now that my little one is starting on cereal because it's easier than trying to pump extra to make oatmeal cereal with.
Good luck!