the problem is not the stairs only, but the whole scene. the scene contains around 1000 meshes (and its not like one building is one mesh, a mesh can be for example all the front sides of several buildings), i would say about 10 percent of the meshes are textured with a solo texture (mostly the ground and road , cars seem to be okay too), the other 90% (buildings and stuff) are mapped on this one texture atlas. i replaced the texture atlas with simple red texture to show which part of my scene is wrong mapped, and i made the stairs green to show the size of this thing lol ... im about to cry if i think about remapping everything that is wrong.
check out this image to see how big the problem is:
http://i.imgur.com/jiSizlP.jpg (size is too big to post it here i guess)
and yeah i could make the scene smaller, cut the parts i dont need and remap the remaining buildings myself, but i plan to render more stuff using this map, since its very realistic and san francisco matches the theme of my project