Yeah, there aren't many (good) FOS quantum chemistry packages, but I'd recommend taking a look at pyscf ( https://github.com/sunqm/pyscf
). I haven't used it myself, but one of the speakers at a conference I attended a few months ago made it sound ridiculously easy to implement new methodologies in it, and if that's true I can't imagine having too much trouble getting more basic calculations to work in it. I doubt the input files will need to be compatible with punch cards :P
's mention of file format shenanigans made me remember another useful tool that I actually have used for a long time: http://openbabel.org/wiki/Main_Page
OpenBabel is a program that can convert chemistry related data files to and from just about any well known format. I don't think it will set up your entire input file for you, but it definitely helps with manipulating/converting geometries. Enjoy!