Aaron, I gotta say, you pretty much nailed my interpretation right down the line, especially the connection between the TV footage of the spaceship attack on the city and Petty's reason for knocking over the Alien Invasion game!
Additionally, I think the vehicle in the beginning is an alien/human tech hybrid that may also be a time machine, and that the Heartbreakers have been going back in time, trying to get together what they need to stop the alien invasion, which explains why their clothing seems to range across various time periods. Note the way Petty regards the coins that come out of the slot machine: I think he sees this as useful currency for when they make their next jaunt back in time.
Unfortunately, I can't help but think that their efforts are doomed to fail. Perhaps others will see a flaw in this interpretation, but I think the Heartbreakers see that footage of them performing in pre-invasion era, and when Campbell picks up the guitar and suddenly plays the solo from "You Got Lucky", they hatch a plan to go back to when that performance happened to make their move on the aliens. Unfortunately, that footage of them playing is proof that they've already tried this plan in the past and failed because of closed-loop time theory. The "You Got Lucky" video was probably a huge influence on Lost.