DONT DO A GALLBLADDER CLEANSE!! if you are experiencing signs of itching you may have some sort of obstruction and a gallbladder cleanse can cause further problems in those circumstance - get medical help before taking matters into your own hands!! sorry i dont know how your heathcare system works but as i said on your previous post you need further investigation as you have symptoms that may be caused by more serious complications!!
What I'm about to say may sound completely antithetical to what you've heard, but hear me out:
Olive oil. Extra virgin.
Start adding that to your food. Eliminate as best you can all sources of fat OTHER than olive oil. (And of course avoid alcohol of any kind) In addition taking dandelion root may help. (There are gallbladder/liver supplements which help thin out the bile. These may help.)
Olive oil thins out bile. I know this from first hand experience. I was told I had biliary dyskinesia; about a year later I was told I developed stones (not unexpected). One gallbladder attack had me in pain for a week. I had a salad wherein I used an olive oil based dressing I made. Within 3 hours the pain, which had lasted for a week, stopped, and I could breathe again. I also took some aloe vera extract to help calm my intestinal tract which had also been hurting. Within 2 days things were back to normal.
Now, I'm not telling you to go on a gallbladder cleanse. These are options for some, but if the stones you have there are too large it won't matter anyway, and if you get a stone lodged in the tract you'll DEFINITELY get your surgery, but not under conditions you'd want. Still, I know for a fact taking adding olive oil to your food may help. At least it may help you hold over until your surgery.
(The dressing I used, btw, consisted of 4 parts olive oil, 2 parts balsamic vinegar (of Modena, the other stuff is just caramel colored wine vinegar), 1 part uncooked honey, 1/2 part turmeric. You can add other herbs if you wish.)
Good luck.