I've beaten all but the 4 Kings. Where do I go?

Title says all, basically. I've beaten the Bed of Chaos, Seath, and Nito and I don't know where to go next really. I've entered the Painted World and there wasn't a boss there so that didn't take me anywhere, and I went and explored New Londo for awhile but I didn't get to any bonfires down there (maybe I'm just dumb and not going the right way). I'm doing my first play through as well so please don't spoil (: I just have no friends that play these games so I have nobody to just point me the right direction unfortunately :/ Praise the Sun!!