You can use unpy2exe to extract the .pyc and then use pyREtic to get the source code. I guess you can read the HOWTO and understand how to use these programs, but basically you go to the location of unpy2exe.py and run:
unpy2exe.py [-h] [-o OUTPUT_DIR] [-p PYTHON_VERSION] filename
thene go to the location of REpdb.py and run:
REpdb.py
set_project [new project name]
Select the python version
fs_um_decompile [location of pyc file]
The source should be in …\Projects[new project name]\sourcecode\fs_um\
Another approach is to take the python byte code dump directly from memory, Immunity Inc published a paper about this subject with a toolkit that takes the bytecode from memory and decompile it to .py source code.
pyREtic