You can via usb, skydrive etc.
steam folder (in program files) --> steamapps --> common --> garry's mod --> garry's mod --> data --> advdupe 2.

There you have it! Just paste the files in there on your new pc via usb/skydrive etc. in this folder

You can via usb, skydrive etc. steam folder (in program files) --> steamapps --> common --> garry's mod --> garry's mod --> data --> advdupe 2. There you have it! Just paste the files in there on your new pc via usb/skydrive etc. in this folder