Still not the actual cover.
The bad news is that the novel is not complete right now and will not be published before Season 6 of Game of Thrones starts airing in mid-April. Martin cautioned that the showrunners will be using his notes and outlines to bring the show (currently expected to end with the eighth season in 2018) to an ending, so some aspects of Season 6 may spoil the final two books in the series. Martin was understandably very disappointed by this, although philosophically it would have only delayed the problem by another year at best: getting A Dream of Spring done before the seventh season next year I think, it will be safe to say, is next to impossible. So the ultimate ending of the story and the ultimate fate of the characters will certainly now be revealed on screen before in the books. That seems likely at this point.
On the positive side of things, Martin believed it was plausible to bring The Winds of Winter to a conclusion with several months of work last year. If that holds true, completion of Winds for publication in late 2016 or early 2017 certainly seems possible. Martin was cautious not to emphasise this point, however, given how badly his estimates have been off so far. He also confirmed that both his British and American publishers can get the book on the shelves within three months of completion, as with the previous three books in the series.
On the other hand, all being well, we will 100% definitely be getting Scott Bakker's new novel The Great Ordeal this year, Scott Lynch's fourth novel Thorn of Emberlain is almost done and seems likely for release, and even The Doors of Stone by Pat Rothfuss has not been ruled out for this year. But the Big One remains MIA, for now.