In my opinion there's really no point in a gallbladder/ Liver Flush before undergoing a procedure for ensuring a healthy liver and gallbladder and of course, firstly breaking up and dissolving the stones in the first place.
As I understand undergoing a procedure such as the flush without breaking up the stones first could be quite dangerous considering the risk of a stone being lodged in a bile duct, or alternatively not flushing any significant stones out at all.

Below I've listed some herbs, supplements and websites I have found of great benefit during my research. I'm sure I've seen these sites posted previously but I find they're of up most importance.

Herbs for parasite/bacterial/fungal infections
- Fresh Garlic(preferably raw)
- Grapeseed extract
- Many more
Herbs for breaking down stones
- Jin Qian Cao (Gold Coin Grass)
- Phyllanthus niruri (Stone Breaker)
Herbs for liver health
- Different combinations of liver herbs are used to suit the individual. A general herb which is considered to be safe and protects the liver cells is Milk Thistle. One should consider taking a herb or supplement which promotes healthy bile flow such as dandelion/chicory(Note: these 2 herbs contain a substance called inulin which could alter blood Sugar levels) or the chinese herb Artemisiae capillaris has been used successfully to stimulate bile production.

Supplements

- Lecithin is a supplement which is used to emulsify fats in the digestive system so it may well be useful supplementing.
- Digestive Enzymes are great to help you digest your meals.
- Omega oils are receiving a lot of attention lately, supplementing flax seed oil every few days may also be of benefit for maintaining healthy cholestorol levels and healthy cells.

Websites

http://www.itmonline.org/arts/gallstones.htm
http://www.sensiblehealth.com/
http://www.rain-tree.com/chanca.htm
http://www.dr-zhang.com/formulas/gall1.htm
http://www.gourmetgarlicgardens.com/
//www.curezone.org

Please don't be an idiot and start shoving all these things down your gob at once as you could cause serious damage to yourself. Be sure to research these things and also try to consult a health care professional about these issues. A little bit of experimentation shouldn't hurt but beware of the risks.

Hope this comes of some help.

If you live in Australia I've found Cathay Herbal supplies Jin Qian Cao in 15g sachets(be aware you can not directly purchase their products from them unless you're a qualified practitioner) so you may want to consult your local practitioner or health care professional who can give you information on these products. Also Medicine Garden Australia supplies Phyllanthus niruri.

Good Luck!