If a car lot sells me a bad car and it has not been very long, what can I do when there is no assistance and they are giving us the runaround?

You can sue the dealership. If they lied or  misrepresented about the shape or condition that the car was in, or if the Lemon Law is violated (you do not indicate which state you are in; the Lemon Law varies by each state, so you need to look up your state's Lemon Law), or if the car had any sort of warranty or guaranty which they are not honoring, then you would have a cause of action. In that event, depending on the circumstances, you might be entitled to either monetary compensation and/or to return the car and get your money back. When there is potential claim or cause  of action, and the other party will not voluntarily make good, you alternative  is to bring a lawsuit. You should consult with an attorney about your situation to see whether  you have a claim and what it might be worth.