Thanks for your help! I did not know about kobesearch.cpan.org...
I realized that I did not mention in my message that I wanted to use GD::Graph module, not only GD...
I also continued to do some research on my own and I found the solution (or should a say a solution). Here it is:
you type the following in cmd:
ppm install http://theoryx5.uwinnipeg.ca/ppms/GD.ppd
ppm install http://theoryx5.uwinnipeg.ca/ppms/GDTextUtil.ppd
ppm install http://theoryx5.uwinnipeg.ca/ppms/GDGraph.ppd
ppm install http://theoryx5.uwinnipeg.ca/ppms/GD-Graph3d.ppd
;)