Been through this with my 13 months old twins - we discovered their allergy when I gave them cheese during weaning as they were bfed - not much fun!
Early weaning is quite straight forward as the usual fruit, veg etc is fine. You can use nutramigen to make up baby rice etc if you're going that route.
After that, is a case of finding substitues you're happy with, or finding recipes that are dairy free anyway.
Dairy free spread is easy to get hold of for sandwiches etc, and use a milk substitute instead of cows milk on cereal, recipes.
Has she been tested for soya allergy? It's common in cows milk allergic children so worth asking for, as it's in so much, bread etc, nad many of the more convincing substitutes are soya based.
Casseroles, spag bol, fish fingers, pastry, baked beans, roast dinners are all fine and regulars in our house. Good luck - it's fine when you get your head round it 