Sadly, doctors know little about nutrition. Most of them know even less about de-tox. For someone with kidney stones, physical de-toxing should be considered. The kidneys (as well as the colon, liver, and skin) are organs that help the body process and get rid of toxins (from food, medications, environment). They can get overburdened due to an unhealthy lifestyle (junk food, soda, coffee, trans fat, etc.). If I were you, I would eliminate caffeine from my diet right away--that means no coffee and no tea unless it's herbal.
Get help from a naturopath who is trained to guide someone through a de-tox. Every person is different. Some people need a colon cleanse (colonic/colon hydrotherapy) first, then a liver and gallbladder flush, then a kidney flush or a lung cleanse. It depends on your history (medications, drugs, lifestyle, esp. food choices, any diseases, operations, etc.).
For some people, it is better to do a colon cleanse before a liver/gallbladder flush so that the colon is in good shape to receive and eliminate the toxins that will be flushed out of the liver/gallbladder. Your naturopath should be able to advise you and devise a de-tox plan custom-made for you. Good luck!