What is Eminem's life story?

I was just watching 8 Mile for the first time and I stopped after like
45 minutes (I couldn't pay attention over my dad snoring. Ugh.). I was
confused about a few things and was wondering if someone could help me
understand...

1. In 8 Mile, who the heck is the little girl that lives with Eminem's
mom? She's a little blond girl. I know it can't be Hailie because I
don't think he had met Kim yet.
2. In 8 Mile, who is Alex? I've never heard of her before.
3. What is his whole story from beginning to present? I want to know
about how he became famous, but also how he met Kim, all of their
relationship problems, things like that. You know, stuff he writes his
songs about. I've always wanted to know his whole story and it's just
now after watching that first 45 minutes that I thought to ask. :)
Thanks.