What formula should I change my daughter too?

My daughter was put on alimentum formula at 2 weeks of age after being extremely colicky and gy on similac and goodstart and it worked wonders. She was a new baby in a matter of 24 hours. She is almost 3 months old now and we want to try and put her back on regular formula but are not sure what to try. I am weary to try a soy formula, but am not sure if that would be better for her sensitive tummy. My husband and I are also lactose intolerant so we are unsure as to whether she may have problems digesting cow's milk.