Clip Map Textures

I need currently working on clipmapping textures. I got to a part where I can correctly update textures when user moves around. But I am having problem on how to map this texture on the terrain quickly.

What I am doing now is, for each detail level I have allocated different textures (using glGenTextures). They all are loaded correctly and when user moves around they are correctly updated too(using torodial stuff). To map the texture in the terrain, I calculate area each textures covers, then enable the texture and texture map it. But the problem is I have to divide terrain depending upon the texture detail level. They have to match up exactly.

here is what my algorithm look like


at beginning

at render function

for i = 0 to max Detail Level
  update Texture at Level i
  find the vertices that belong to texture level i
  bind texture at level i
  draw vertices that belong to texture level i


Is there other way of doing it.Do I have to use multi-textureing?? Are there any special extensions used??