Allow me to attempt to help.
I don't know the exact numbers involved in Earths luminosity but I think that's not really important for what you want to know. I assume you're interested in our ability to be detected by possible intelligence at reasonable distances, which would have to run into the 100's of light years at a minimum to even have a hope in hell of actually reaching some form of intelligence.
Well, it depends what you mean by detection. Detection of the human race on Earth or detection of the ability of Earth to support intelligent life.
The latter is quite promising. With telescopes of the same capability or slightly better than what we have - and who wants to find a race dumber than us anyway - we are very detectable. Probably from 1000's of light years away. And they would also be able to spectroscopically detect light reflected from the atmosphere of Earth and detect methane and oxygen which would make us stick out as a promising target for intelligence and confirm Earth as a living world. But they still wouldn't be sure if anything like intelligence had yet developed.
So Earth is not that hard for an alien species to detect under those criteria even from a rather distant species.
As for radiowaves that's a whole different kettle of fish. I think you're all being pretty generous by saying we've been kicking out radiowaves for 100 years. Sure we've had that technology for that long but upto about the latter half of WW2 we were mostly using low freqency AM radio that tends to be refracted by the Earths ionosphere and thus rarely makes it into space, above and beyond. Since then of course we've had much more high frquency powered radiowaves and such, and those do escape into space with ease.
But even with megawatt transmissions they're still going to be pretty weak by the time they reach say, 100 light years away, and of course these aliens would need huge SETI type recievers to detect the signals. Military radar and the like are much better candidates for being detected due to the higher power they use but still we're going to have to be VERY generous to say that we are detectable through these means upto 100 light years away. I'm not sure of the exact distance but it's around that.
So conceivably thousands of stars within our immediate vicinity, upto say, 50-100 light years can watch our TV without paying their TV licences and of course the distance keeps on reaching further day in, day out, but I'm not going to get my hopes up for intlligent life within 100 light years. I just doubt it. 1000 or so, yes. So we probably have allready been detected. I'd say that wasn't that much of a science fiction stretch whatsoever. They just can't be sure if there is intelligence here, but I'm sure Earth is listed as a possible subject for intelligent life by some civilization somewhere.
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