Whats the best way to stop a bad tooth ach when Advil (ibuprofen) doesn't work anymore?

Get to a Dentist. Dental pain from an abscess can be a good thing. If the abscess extends into your brain you can have some real problems, so listen to your body.
Call your dentist. If you have a persistent toothache despite taking anti inflammatory medications discuss with your dentist for an appropriate diagnosis and treatment plan.