You need to install the toolchain for the architecture you are targeting. Search for "cctools" / "binutils" / "crosstools" or "ppc cross-compile environment".
You can also take a look at:
- Building and Testing gcc/glibc cross toolchains (This will probably work)
- Host/Target specific installation notes for GCC (search powerpc in the page)
However, I would encourage you to try this on a linux or on a mac computer. There are far more resources & docs available on the web for cross-compilation on these platforms.