JillM, has this been diagnosed by a doctor or dietitian, and is she fully formula fed? If so, they should be able to advise and/or prescribe a suitable formula - you can get 'pre-digested' versions which are less likely to provoke reactions, but they are probably very expensive if you try to buy them yourself. If you haven't seen a doctor about it yet, you could try - I know (from my experience) that you have to be determined to get them to realise you are serious and that you have investigated it fully, but once they believe you they should be able to offer you options.
Are you thinking about the 1yr cut-off because that's when many people start giving their children normal cow's milk as opposed to formula? I don't think you necessarily have to switch at this stage, whatever baby milk she's been drinking is probably still good for her.
if your dd is breastfed you shouldn't have to worry about finding a 'milk' subsitute, although you might have to cut cow's milk out of your diet, and make sure you offer her lots of food with calcium (e.g. hoummous, bread, eggs, calcium fortified juice, sardines or salmon with bones, figs, seeds). There are some good ideas for non-dairy calcium foods on the Vegan Society website. The people on the 'allergies' topic will probably give you some other good ideas.
Approx 60% of milk intolerant children also develop reactions to soya, so that's a good reason why you shouldn't give soya formula to your dd. (My ds1 had cow's milk intolerance and I had very bad advice, gave him soya formula from about 8 months and he then developed a reaction to it. Now (4yo) he can tolerate small amounts of cow's milk protein but soya is still a problem - and it is in virtually every food so very hard to avoid.)
Soya formula tends to be more sugary than standard formulas, another reason to avoid it. Also, soya formula has been around for less time than cow's milk based formula, so the 'experts' say that it is not as well developed, although I'm dubious about this statement given that the general public is given very little information about how normal formula is created. I have also seen research that implies that if a child is doing okay on soya formula, there's no reason to change them, so your kids should still be alright psychomum5.
If you're thinking about the soya 'milks' that adults use, they are not as nutritionally complete as a formula, so that's another reason it is suggested to leave them until children are older.
Children intolerant to cow's milk can also develop reactions to goat's milk if they have too much of it, so although some people use it as an alternative I would recommend introducing it slowly instead of using it as your main milk substitute. My ds now eats goat's cheese quite happily but has calcium fortified rice-milk on his cereal. It seems that if you want to avoid reactions it's important not to depend too strongly on one food source.
Sorry, don't know how fully you have investigated this, so apologies if you know all the information on this page already, however \link{http://www.eatwell.gov.uk/healthissues/foodintolerance/foodintolerancetypes/milkallergy/?view=textonly\this page} is a useful summary of the issues with milk intolerance or allergy.
hope that helps