I was in an accident that involved a uninsured and unlicensed driver, but I was told that I was at fault do to that I didn't yield to the left.

You said you were "told" that you were at fault.  Who told you?  If that was a court determination, it is binding, but if not, you can still sue and claim that the other party was at least partially at fault.  However, the fact that the other driver was uninsured and unlicensed did not cause the accident.  If you want to prevail, you will have to assert some other basis for why the other driver is completely or partially at fault.