Hello and thank you for posting your medical query on E health forum.
From the history provided, you seem to have small gall stones. In case you are not symptomatic until now and gall stones were diagnosed incidentally, there is no need to have any fear. Dietary modification and physical exercise will help to control obesity and also help to reduce your gall stones.
As far as herbal medications are concerned, some herbs such as barberry bark, Wild yam root, Cramp bark, fennel seeds , ginger root, catnip herb and peppermint leaves have been found to be useful to help in reducing gall stones. But the use of such preparations that are available should be better taken after consulting your physician, who can rule out any medical condition that may contraindicate their use by you.
I Hope this is helpful.