If I understand what you need correctly, it just as simple as this:
1. Open the drawing
2. Delete all layout but one you want to keep;
3 Save the drawing "AS" a new name.
Say, you have drawing that contains 3 layouts (named as L1, L2 and L3).
Your code open the drawing "TheDrawing.dwg"; delete L2 and L3; save it as "TheDrawing_L1.dwg".
Then the code open the drawing "TheDrawing.dwg" again; delete L1 and L3; save it as "TheDrawing_L2.dwg".
...You can go and go to clear out all layout except for the one you want to keep and save the drawing AS whatever name you like.
The code for doing this would be fairly simple.