The Voyager is transmitting from beyond the heliopause (About 17,600 Solar Diameters according to Google).
Up the power, repeat the message on a rotating directional transmitter. Use the emergency frequency and the thousands of years old emergency signal prefix. That signal will be detectable by any space faring sensor within the system. If for no other reason than that the sensor will be programmed to scan for and amplify such signals automatically. Even the basic ones.
Finding, and more relevantly - identifying, a ship that is just puttering along is where the sensor ranges come into play.