How can I get paid from Sept. 2015 until current date for taking care of my ex aunt in-law?

Your ex-aunt-inlaw can pay you to be her caregiver. You would need to prepare an employment contract stating how many hours per day, what are your duties, and what is the hourly rate. But you would need to pay payroll taxes. Good luck, as the vast majority of caregivers do not get paid [unless one works for a caregiving Agency].

Unless you had an agreement in place in advance to take care of her, you DON'T get paid. State programs would be through Medicaid or Long Term Care Insurance and it would have required a caregiver agreement be in place. Sorry you did all that work for her without being paid, but there is no retroactive caregiver pay from State or Federal Government in the US.