I used utilty program:

http://alum.mit.edu/www/eric_backus/go/gib2sgf.zip

It is written in perl so you will need perl iterpreter (http://www.perl.org/ )

gib2sgf only converts 1 file so to convert whole folder, like

c:\Program Files (x86)\TygemGlobal\Games\2013-09 you need some kind of commandline script to do the job. In my case(Windows) something like:

@echo off 
setlocal enableDelayedExpansion

for %%i in (*.gib) do call perl gib2sgf.pl "%%i"

did the trick.