Gastro oesophagal reflux diagnosed.

My 4.5 month old son diagnosed with gastro oesophagal reflux . Diagnosed by GER milk scan. The findings in the report say 'mild episodes of abnormal reflux of radio tracer activity were seen from the stomach into the oesophagus during the dynamic phase of the study' Impression: scintigraphic evidence of gastro oesophagal reflux is seen in the study'. The frequent vomits made us do this scan. His current weight is 5.40 kg., Which is worrying us. The baby is active otherwise. We are feeding him nanpro formula as the breast milk is inadequate. What next? Kindly advise . Every day average 450 ml  Formula. Vomit frequency is different everyday 3 to 10per day.. where are we going wrong.? What next.? How much to worry and how to go ahead?