When you say that you can’t get at the remaining space, what exactly do you mean?
Because you can’t write to the filesystem directly while using the USB, because the filesystem still believes it is on a read-only CD rom.
Or, do you mean that the disk is now full? If so, you made your persistence file (the place where you store your changes) so large that it takes up all of the remaining space.
2GB isn’t a lot for a USB startup disk. I’ve run out of space on a 4gb before. Depends on how much you want to install.
Do you have persistence working? In other words, if you save a file on your USB stick’s desktop, is it still there the next time you boot with it?
Also, when you make a live USB boot disk using Ubuntu, you are given the option of how large you want to make your persistence file, or whether or not you even have one.
If you give me more information, I can help you. Freepmail me if you want.
I currently have a 32gb pen drive with a 6 GB Ubuntu partition and a 26 GB storage partition. Pretty cool.
I have a distro of SUSE11 on a 500Gb portable drive, I love it, I can literally take my computer any place and run it. Just plug the drive into a usb port and turn on the machine. Most computers are set to boot from the usb port before the hard drive.