Steps to install pyQt5 (with VS 2012) on Windows:
1) Install the binary file Qt 5.0.2 for Windows 64-bit (VS 2012, 500 MB) from here.
2) Get sip-4.14.7 (development snapshot) from here.
3) Extract the file and open the Developer Command Prompt for VS2012.
4) Execute these commands (in sip folder):
python configure.py
nmake
nmake install