Before I got pregnant I had horrible heartburn and I took prescription omeprozol to treat it (forgot how to spell it) and it worked wonders, since I have been pregnant I haven't really had heartburn so I don't know if it's safe to take during pregnancy but I would definitely ask your doctor. If it is safe you can either get it prescribed or over the counter in lower doses at pretty much any store with medicine.
My hubby makes me eat apples with carbonated water with lemon juice squeezed in. Also basil if its around. It helps a bit for a natural route.
Liquid antacids are supposed to be lower sodium if you're going to take them. I also eat many very small meals now. Don't lie down for at least 30 mins after eating.
Hope you find dinner relief. Its no fun having heartburn