Hello alejandro_blue,this is a very specific topic, GIS is something I personally never dealt with... But managing databases sounds like a very "tame" thing, it sounds like there would be lot's of great options with free libre software.
A quick look at wikipedia reveals, there are many projects devloping GIS software under a GNU GPL license:
* GRASS GIS * QGIS * OpenJUMP * DIVA-GIS
