Just Purchased Fallout 3?

Ok. So I just bought a pre-owned copy of Fallout 3 from gamestop today. I've never played any of the other ones so I wasn't sure exactly what I was getting myself into, but I seem to be having trouble well..liking the game. The worker at the store raved about how awesome it is, and it's a pretty common fact that it's a popular game so I don't doubt it's good, but I'm not really enjoying myself. It reminds me alot of Elder Scrolls Oblivion (which I played for a day and returned) . Not trying to hate on the game itself, but idunno. I'm not feelin it. I broke out of vault 101, made it to Megaton, talked to a few people and did a couple of minor quests, but now I'm at this part where I'm supposed to give the owner of the saloon 100 caps for info on where my dad went, and I don't have the money. I don't know how to make it. I made the "good guy" decision with the chick he wanted me to get the money from so I didn't get it from her. And anyway, I'm just stuck. The game is so open ended and isn't really giving me any sort of clues as to wtf I'm supposed to be doing at any given time. The so called "objective markers" are very vague and hard to find and idunno, I guess i need a little more F'n guidance than that to get me going before you can just throw me out in the world and say "figure it out." It doesn't make sense that I'm allowed into all areas of the game already either seeing as I couldn't even hold my own against the creatures in alot of the areas yet. I really want to give the game a chance so if someone could just tell me what i'm doing wrong in general? Or what I should be doing? That would be awesome. Sorry for the rambling guys. Peace.