They got the ship in that episode when the asteroids were going to hit that space station. I forget the name. I think D'Argo just saw it floating out there and "recognized" it as important somehow.
"Suns and Lovers," from the very beginning of Season 3. It was floating outside the space station and they rescued it. There wasn't a whole lot explained about it other than it seems to be of ancient Luxan design.
Chiana's visions started after she was inhabited by the Energy Rider, so that's the common theory about the cause. However, they were never really explained and they actually seemed to change in nature after a while.
Yeah, after she was possessed by the Energy Rider in "Losing Time," she began to exhibit weird powers. They started subtle at the end of that episode, when John asked where D'Argo was and Chiana knew (without looking) that he was entering that room. Her powers got more intense towards the end of the season when she "saw" Moya being swallowed by the wormhole.
During the break between Season 3 and 4, her powers continued to change, and she found herself able to see slow time down (or at least her perception of it), which she used to cheat at gambling. Authorities caught her, imprisoned her for a while, and treated her like trash, which is why she's a lot more twitchy and angry at the beginning of Season 4.