Getting a 64-bit installation of Python with scientific packages on our dear Windows isn’t as simple as running an apt-get or port command. There is an official 64-bit Python build available but extensions like numpy, scipy or matplotlib only have official 32-bit builds. There are commercial distributions such as Enthought that offer all the packages built in 64-bit but at around 200$ per license, this was not an option for me.
Stumbled upon the Python Extension Packages for Windows page that contains dozens of extensions compiled for Python 2.5, 2.6 and 2.7 in 32 and 64 bits. With these packages, I was able to get a working installation in no time.