granturismo concept...

hi... i just downloaded all the necessary files for gt concept...
i have about 70 files... i have gt-concept.001 through .70
i used winrar to unrar the files and whenever i try to unrar i get the following message:
you need to have the following volume to continue extraction:
gt-concept.001.r00
i don't know what the problem is... im pretty sure i have all the files... can someone plz help me on this?
this is my first time doing all this extraction stuff... if anybody knows how to do this email me?
tidus625********com

thanks in advance...