The problem is that all of those outlets and fixtures are on a single circuit. That means a single cable. The circuit breaker is merely the beginning of that circuit run.
What you need is more wire, not just more breakers. You would have to run a separate wire from one or more of those outlets and fixtures to the panel box, and then you could add a new breaker. Supplement: You would, of course, disconnect these outlets and fixtures from the original circuit.
Also, though you do not suggest it, please do not even consider changing to a higher amperage breaker. The amperage is again controlled by the wire (in this case, size), not the breaker.