In preparation of the V1.2 release I uploaded an updated build script and the patches for gcc and binutils.
These files are in a special package called avr-ada-1.2.0p.tar.bz2
For building your cross compiler you will need a unix-ish environment, either Debian or Windows with the latests MinGW. You also need a native gcc-4.7 Ada compiler. Probably you will have to build that first before delving into building the AVR-Ada compiler.