Fallout 3's DLC

Operation Anchorage is hitting the streets, but not being a PC/360 owner - it's not entirely relevant to me. As I said before, though, I'm still playing the main game ... so why do I care?

Apparently this add on works by having players pick up a new signal to find the missions. Which feels a little off to me. If I just paid for new content - should I really have to hunt the wasteland looking for it? I'm probably misreading things, maybe the DLC tells you to head off to the northwest area or something.

Finally - an upcoming DLC will raise the level cap. Before I hit level 20, I didn't think about that much. Now that I'm bouncing around the DC area, blowing off the heads of pretty much everything around me - I must ask, why? Do I need ten more levels to raise what ... my barter skills? Big Guns?