I'm so sorry. I know how you feel because my boy was 11 when we went through it with him. One thing I can say is that after the surgery to remove them, the stones never did come back. But we lost him to cancer in March at 12 yrs old.
$1,100-$1,200 seems very high to me. My Thorin weighed 76 pounds, was neutered at the same time the stones were removed and it cost us just over $800. We had it done at a clinic in Devon. The smaller, surrounding area vets are much more reasonable, but if you do go that route, make sure you check reviews before taking your baby to anyone. Good luck