Sky started "breaking bad" some time ago and at this point is completely bad. She succumbed to greed -- like many of us would have in the same situation. I don't think Skylar is as bad as Walt, but she ain't no saint either.
I don't know. I never got the sense that the money really mattered that much to Skyler. She gradually started helping out more and more with the business, but I think that was mainly just for the small thrill she got from doing something illegal, and because she wanted to ensure that Walt would actually get away
with this thing he was doing (and look as clean as possible to the outside world).
I think Skyler's main goal through all of this was just to not destroy the family and prevent Junior from learning the truth (after her plan to divorce Walt and throw him out of the house failed so badly). At this point she's just going along with Walt's plan, it seems to me, because it's about the only course that's really left