You can try frequently calling your doctor's office and asking if they have any cancellations. That way, if you get lucky, you might get seen much sooner than July, as long as you're willing to go there on a moment's notice.
It sounds like you're in the VA system? That's notoriously slow, especially for low-priority patients who have a low disability percentage. And I'm guessing they won't pay for a specialist if they didn't refer you to that specialist. Do you have any other coverage? Any other doctors you could go see? Is it possible you qualify for Medicaid?
If necessary, you might try medical tourism. Go to a country where medical care is cheap and see a specialist there, out of pocket. The trip and the doctor combined may still be significantly cheaper than seeing an American doctor.