You're back on Manhattan; sell the Cardamine.
And you're done with the story. Orillion says he'll be in touch, but that seems to mean in a sequel (which never came to be). There's still lots to see out there, though. Travel around through the systems you haven't seen yet. Visit the homeworlds of the Corsairs and Outcasts. Upgrade to a ship that can carry level 10 guns, and fight Nomads to get some of their guns. Visit the planets of apes and robots.
You are now at least level 18; now that you're done with the story, your level depends on how much money you've made. Max level (38) seems to be at around $2.4 million.