An alternative approach is to use the excellent WinPython distribution -
http://winpython.sourceforge.net/. Its a single package you download that includes python, most of the popular packages (numpy, scipy, etc), and qt support (both PyQt and PySide). It does not include pyqtgraph by default, but the installer for version 0.9.8 can be used through WinPython's package manager to easily install it. Probably the easiest way to get it working.
Also, I've had fairly good luck doing Python 3, as most of the major packages support it now, and pyqtgraph seems to run well under it now.