I will also jump in on this with Wim's wife Ann...
The food you were feeding her before might have caused the stone. The pet food recall concerning the melamine is centered around kidney issues. If you haven't checked the list of recalled foods please go to http://www.howl911.com/
If your cat was eating any of the recalled foods she needs to have treatment for it. You also need to stop feeding your cat any food that was on the list.
My cat died from probable kidney failure due to pet food.

Wim, knows his homeopathy. He is very skilled in treating pets and their problems. Please take his advice on this. Kidney or bladder stones do not get smaller on their own. They get bigger.

Julie