you will need 2 dual layer disks (one for east and one for west) and a dual layer burner. The navigation disks are 8 gigabytes a piece and they cannot be compressed to fit onto a DVD-R or DVD+R. If you do not have a Dual Layer disk there hasn't been a way to copy the navigation disk.
So to some up you will need 2 dual layer disks (8.5 gigabytes per disk) and one dual layer dvd burner and a copy of Nero or Alcohol 120% or CD Creator .