Before trying home remedies, please take your dog to the vet if you think your pet has a UTI or bladder stones. Not only did I miss signs (hindsight is 20/20), but so did the vet. Make sure they check for diabetes. I lost my little doxie to diabetes complications. We didn't know she had it until she was in a crash situation. The vet never mentioned this as a possiblility causing UTIs--her sugar spiked to 530 and she had ketoacidosis. Her kidneys failed and we lost her in 3 days.
Be safe--always check for diabetes!!!