My granddaughter, that I am raising, had a real problem the first 2 months of life. She spit up more than normal and stopped breathing on occasion. Finally she was diagnosed with an esophagus that doesn't function properly so food stayed there. Then as the stomach was empty, it's acids was rise up and push formula til it blocked her airway. Docs put her on Prevacid (calms the acid) and Good Start Soy formula.
Anyways, we were receiving WIC and all we had to do was get a "formula doc" and a prescription from doctor and the WIC program gave us the soy formula each month. Have you checked with your WIC office to see if this is possible? I am in Wisconsin and I see you are in Illinois, but I believe most WIC programs are very similar. Explain the issues with your child's Gerd (acid reflux) and that your current formula seems to do better for him.