Looks like a pre-war Clausing and it is probably a very usable machine if it is not too sloppy. What tooling you will need is a good question but the list is endless and I would suggest not spending much on anything that will not be usable on a newer machine. I would suggest buying only what you really need at first and, in all due respect to Mikes suggestion, a quick change tool post would be nice but not really necessary IMO and the $200 or so it would cost would buy a lot of bits and other parts. A good live center for the tail stock and a drill chuck are almost "have to haves" and of course you will need a dial indicator with stand, mics, calipers, etc.
Be warned, you are about to become addicted to a habit that will be impossible to break!