How to organize and distribute a Python Application with C extensions?

Question

I'm working on a Python application that is distributed as source (zipped) and via py2exe (majority).

Now I want to speed up some modules by replacing them with C extensions. Which works quite well for the development part. But the distribution and organization gives me a headache...

My current structure looks like this:

.
|-- py_submodule_a/
|-- py_submodule_b/
|   |-- c_extension_ba/
|-- c_extension_x/
|-- setup.py
|-- main.py

My question is, where should I place the setup calls/files for my C extensions? I want to make sure that I can always run my application via main.py (so I'd rather not wait until distribution to compile the C extensions) but I also want to make sure that the distribution always has the latest C extensions.

Thanks in advance for any help!