it was very hard to find this strangely. It seems that its was not connected to the regular gurps website. Even if it is 3rd Edition, the file is editable and what has changed can be applied.
Anyway it is Thomas Bont's GTS program that I was looking for. I seemed to lose my copy, and given the scare it being lost forever, I might as well make this link available.
There are some old spreadsheets like: GURPS robots and Solar System Constructor that could probably worth saving in Google Docs.
Steve Jackson Games: Computer Aids For Our Games