You might want to try the Liver Flush that calls for orthophosphoric acid (see this flush along with others on the Liver Flush page). This flush requires that you drink unpasteurized organic apple juice during the week prior to the flush, and adding orthophosphoric acid to it. The combination of malic acid from apples and the orthophosphoric acid helps to break down Gallstones a bit before they are eliminated. There are also herbs (some chinese) that are also reported to disolve gallstones...although I have not used any of them so I can't say how effective they are.
Perhaps others who have used any herbs for this purpose will also respond.