A warning about this series– don’t become too attached to any one character. Martin will tease you with one possible storyline and then in one (usually violent) episode everything changes. This keeps things interesting, but he killed off characters whose future plans I was deeply involved in. Afterward, whenever another character was in danger, I found myself thinking, ‘Is he going to kill this one off, too? No one will be left.’
I can assure you that there are plenty of characters left to continue the series. Even so, your favorite surviving character may not be in the next book. Martin’s next installment had gotten so long that he decided to make it two books and instead of cutting it in the middle of the story he has split it by characters, so the next two books will actually be parallel in time.