Extract the apk of Live wallpapers
You can use ES File Exporer  


Goto App Manager (press menu to get app manager)
There you can see list of applications installed in your mobile
Select Live wallpaper apk  
click on Backup  
You can find apk in location /sdcard/backups/apps  


*Edit:*    

System Live Wallpapers are located on your phone in path:  


  system/app/LiveWallpapers.apk  


You can use ES File Explorer for the same.
But your device need to be rooted to access system apps.