Group Giveaway - Levels?

In short:
Yes.

Long answer:
As long as a GA gets 5 entries, it will count towards level. Public GAs are excluded from this rule, any number of entries in a public GA will give CV.

and is there any graph showing me how much $$ of gifts I have to give in order to advance to another level?

Yes.

All giveaways that have at least 5 entries into them will count.

As long as at least 5 people enter the giveaway, as I remember.

Ok, what about contributor levels? How many $$ do I need to give away in order to advance to another level? How does it work?