It appears he published it in weekly serial form in Household Words - which he edited himself - during the early part of 1854, and the book came out on 7th August that year, one week before the publication of the final installment in the magazine. That was seen as a clever way of boosting sales, and was normal practice.

His practice was to write the episodes as he went along, rather than write the book and chop it up into episodes. That meant sometimes that the plot was affected by the public response - that was especially true with Martin Chuzzlewit, which was in monthly parts, and published in a magazine he didn't edit himself. The American sections of that hadn't been originally intended, I believe.

Stephen Foster's song was actually published in early 1855 - "Foster's "Hard Times Come Again No More," published in early 1855, was both a reflection of recent events in his personal life and a portent of things to come. He and Jane separated for a time in 1853 and his close friend, Charles Shiras, died during that same period. During 1855, both his parents died. (From here)