This is Dr. Christian. Welcome to JustAnswer. A few questions will help me get a clearer picture of the situation:
Does she urinate in small, frequent amounts or does she produce a lot of urine when she goes? Does she seem to strain when she urinates?
Thank you for the information. Sorry about all the questions but I'm trying to get a good idea of the situation. What you are describing is called pollakiuria. It means frequent, small urinations. It is typically caused by bladder pain. When the bladder is painful even a small amount of urine causes an urge to urinate. I suspect that a urinalysis would show blood even though it is not evident to the naked eye. Here are some possible causes:
Bladder cancer would be highly unlikely at this age. A urinary tract infection is the most likely cause. Avoid the garlic since garlic and onion both can be toxic to dogs and cause anemia. Cranberry juice mixed with her water may help a little but certainly won't fix the problem. Aleve is dangerous in dogs. The safest over the counter pain medication is aspirin. You can give one 325mg buffered aspirin every 12 hour for pain. It can be given for 3-4 days before it can cause stomch problems. It is best to have her seen by a vet. A urinary tract infection, if untreated, can actually move into the kidneys and cause severe illness. Antibiotics are very effective and work quickly. If you have more questions please let me know.