Expand memory by USB

hey there…

I’m running Ubuntu 13.10 with Command line. I want to install the GUI (sudo apt-get install ubuntu-desktop), but it says I dont have enough space in the emmc.

So I connected a flash drive. But still BBB tries to download and install ubuntu-desktop to the emmc.
When I run fdisk -l it says Disk dev/mmcblk0boot0 doesnt contain a valid partition table. Disk /dev/sda: 7822 MB

How can i download and install ubuntu-desktop ???

Boot with a 4GB or greater microSD card.

Regards,