How you generate the gcode probably depends on the machine you are sending it to. For example, to print an object with a plastic printer like a reprap, save it as an stl file, then use Slic3r to generate the code....
Other 'free/open source' generators here:
http://replicat.org/generators
It takes a while to get solidworks, but we use it. The school contact has to request it, then they mail the discs.
If you need converted sooner, you can either email me the files, or send me a link to them, and I'll load them into solidworks and save them in a format you can use. Send me a PM if you want me to convert.....