First off, voyager is small, lightweight, off in the middle of nowhere, and only has a low powered (couldn't even be as much as 420 W, on average) and narrow radio beam.
Considering that it is, and always will be, close to earth (it takes what, about 20,000 years to move 1 lightyear?), anybody capable of finding it can directly find the earth far easier, considering that multi-megawatt radar systems, and similar sources of recognizable oddity, are common on this planet.
This shell of radio emissions is a century thick and traveling at the speed of light, by the way. Which makes it way easier to find than some silly 3/4 ton chunk of metal.
Hell, any spacefaring civilization advanced enough to be a problem probably doesn't need to see our radio emissions. Considering that it is basically possible for us humans to do it right now, it is reasonably likely that "they" know that earth has life on it from spectral analysis of earth's atmosphere, or similar measurements. And that we just underwent the industrial revolution, most likely, considering the changes that event brought upon the atmosphere.
(The above points fail to hold if the civilization has FTL travel of some sort. Then it could be both too far away to find us AND be able to get to us quickly and inexpensively. It also means our understanding of physics is incorrect - though it still seems like they should be able to find earth easier than some half-dead probe.)