first you should already install NetFrameWork 4.0 in your system.Link here:Link
then you should download this application too,link here:Link
Then open the app and as you can see in this picture:LinkClick on Set GP to Max
after Click on "File" Menu and choose save then open your OPTION.bin file and save it.
as you can see in this picture,Linkyour GP is set to max and now you are free to buy all things that you want in Extra option in your PES2011 game.
this work for any other version of the PES2011 too...