Automating software and custom plugin installation on Mac & PC

I am building a 3D printer and using the Repetier-Host slicer to generate the gcode from a .stl file using the Skeinforge engine. I currently have a python script ([login to view URL]) that adds a plugin to Skeinforge to run a post-processing script ([login to view URL]) on the gcode. Right now post-processing works with Skeinforge after installing Repetier Host and going through a 9-10 step installation process. I want to cut this down to a one step process - the client gets a software package with an executable, runs it, and viola! Repetier-Host is up and running with post-processing activated (and the option to toggle this activation through Skeinforge). What we need is pretty much one simple script to automate the installation process documented in the readme file attached. The default installation for this package should be in the Program Files folder on Windows 7 & 8, and Applications folder on Mac. We need both versions, as well as one for Linux. This should be a fairly straightforward project, but please contact me with any questions or clarifications. If you are interested in this project, I can send you the files referenced above. Thanks!