As far as the convincing every human on Earth, it's easy. Fly up to the aliens, and ask them to do as the Vorgon guys from the Hitch-Hiker's Guide To The Galaxy did (but only in the novel!):
Getting Every Human On Earth To Believe That The Aliens Are Here To Save Them: For Dummies (A Guide For The Rest Of Us!)
Also known as: GEHOETBTTAAHTSTFDAGFTROU (Pronounced: The Guide)
To be narrated over the top of "The Entertainer"
Step 1: Grab a microphone that has a lot of feed-back, and is inconvieniently located on the roof of you're millions-of-stories tall bridge (as in, control room).
Step 2: Speak (QUIETLY! Remember the feed-back) into the microphone, telling the humans of Earth of their impending doom. Don't worry, they'll all hear it, 'cause the sound will be amplified off every window, trash-can lid, and so on.
Step 3: Watch panic unfold (except for that woman in the movie who just shakes her head and continues reading).
Step 4: When the panic dies down (1 to 2 hours), explain that this won't happen for a couple of years, and that you're here to help.
Step 5: Quickly say that you aren't Jesus, The Headless Horseman or any of that other religious nonsense, before the Pope beats you to it. If he says anything, you may as well leave.
Step 6: If he hasn't already, God, Zeus, Mohammed and the rest will be knocking on you're door, asking if they get a seat on you're super-awesome ship. Let 'em in or leave 'em, it's you're choice.
Step 7: Wait for the humans to come to you. Remember to have an equatorial orbit!
EDIT: On second thoughts, why would anyone save us? We would probably blow up the ship on the way to Earth 2.0, and if we didn't then we would probably stuff up Earth 2.0 like we did 1.0.