Good for you for taking your health into your own hands. First of all cancel that appointment and give yourself a couple of months to make some changes in your diet. Then you always have that option, but there is no going back after surgery. And surgery did not fix my ploblems.......flushing did. Here is a link to some of my postings.
Read as much of the liver Flush FAQ 's as you can. Also read the information on diet and fats on the links at the top of the pages.
You can start dissolving/softening the stones with some products from www.sensiblehealth.com On that site is a wealth of information too.
I do not believe that you have to do a parasite cleanse first, but most people will benefit from that after several liver flushes. The Hulda Clark flush is easy for beginners to do.
We are all here for you for questions and concerns too.
Try to plan to do some flushing real soon.