http://matplotlib.org/downloads.html
import matplotlib.pyplot as plt
You need to install it on your system. This basically means putting the zip file where Python can find it, but by far the easiest way is pip install six. This will download it a second time, though.
Like the matplotlib installation instructions mention, six is a dependency of the dateutil package. Most sane installation methods would pull in this dependency automatically; if you had done pip install dateutil in the first place, this missing dependency should have been satisfied behind the scenes. If you require a completely manual installation, you should give those instructions a thorough read.
datautil
http://www.lfd.uci.edu/~gohlke/pythonlibs/
ImportError: matplotlib requires pyparsing
http://www.lfd.uci.edu/~gohlke/pythonlibs/
install six
C:Python27Scripts>pip install six