I'm posting this here not because I solved the problem myself but because it was a mighty faff to find the right way to get this thing working without downloading the files via apt-get. It does work (in the end) - here are the steps:

  • Since you don't have an internet connection you'll need to download these two three files: realtek-8188cus-wireless-drivers-3444749-ubuntu-1304, realtek-8188cus-wireless-drivers-3444749-ubuntu-1304 and DKMS (on which the driver relies)
  • Navigate to your downloads folder in terminal and install the DKMS dep: dpkg -i _________.deb
  • Install the drivers
  • Blacklist the old drivers sudo gedit /etc/modprobe.d/blacklist.conf by adding the following lines:
    # Blacklist native RealTek 8188CUs drivers
    blacklist rtl8192cu
    blacklist rtl8192c_common
    blacklist rtlwifi
  • Remove the wifi card and reboot