Does a failed torque converter equal a new transmission?

What is your question?

I replaced the transmission in my car about two weeks ago. Now it will cut off when driving at low speeds,shake violently, and over heat. I have not had anyone look at it but when I told a mechanic friend he says that I need s new torque converter. Well, does this mean replacing the transmission again? would the one I just bought have come with a torque converter? Or are they sold seperately?