Melissa,

The circuit to an outside lamp should have been fed by a GFCI. The
circuit feeding your bedroom and living room lights would not be. get
the electrician to trace the circuit and split it into two circuits.
Or tie the OD light into an existing GFCI(ground fault circuit
interruptor). I have an electronic circuit tracer that puts a radio
signal into the wires so the wires can be traced, even underground if
not too deep. A good electrician should have one too.

Stretch