I don't do this and have only watched someone stream once so I don't know for certain but from what I know and thing off these are the steps in order to stream what you do:

1.) Get This

2.) Make a Twitch account

*optional*

3.) Get a webcam so people can see you while you are live streaming.

Sorry if you need more than that as I have said before I have only watched live streaming 1 time and have never even had the need to do it, this is just what I am guessing you will need in order to do it.

Edit--------------

being lazy and only reaad your opening title lol, the only thing I would say that is desperately needed to upgrade would be your GPU.