Have you tried Gax-x? It'll have to be while the gas is in your stomach. Once it gets to the intestine, there's only one way out. Also, if you eat gassy foods (beans, etc.) try Beano. I take about 3 just before eating the food, and it seems to help a lot. I actually had chili last night, and the Beano did the trick.
Are you staying away from carbonated drinks? Also, don't talk while you eat...you'll swallow a lot more air. I've heard many times that people with GERD swallow a lot more air than others.
Give it a try! Hang in there...