bot47,
Is the source available for download? You say it's GPL'd... Also, don't forget that you are distributing other GPL'd software with your installer, so you need to comply with their licenses.
I can't comment on the installer itself (I don't use Windows), but I'm hoping that one of the now numerous Windows installers could become more official, and be included in the installation Wiki page. If anyone has used this (or another installer), please give some feedback.