I'd definitely recommend starting on Fallout 3 next. Once you get out of the shelter and get going in the wastelands you'll love it.

I have no freakin idea what kthxbye stands for, but I certainly didn't post any spoilers whatsoever. Hell, I haven't even played the GNR level yet, as I said, I talked my way out of it. Since you are out of the shelter, it is no secret to you that your dad ran off and your mission is to track him down, so it should be no spoiler that eventually somebody tells you where he is. The fact that some dude needs you to repair something should be no spoiler either, since there are about a million people in the game that ask you to do favors for them by fixing something they are too lazy to deal with themselves. I guess the mutants in Jefferson Memorial could be a spoiler (comes much later than GNR though), but the fact that Mutants pretty much occupy every above ground building in that area should come as no surprise that a few of them hang out there. That would be about as big of a spoiler as me saying there are ghouls in the subways.

Wow, you are at level 13 and you haven't done any of the story missions beyond the shelter? This game is going to be damn easy for you.