Wubi indeed does not create a partition but creates a file in your Windows partition and mounts it as a loopback device (a way for Linux to access a file as if it was a partition).
The file should be under program files, under wubi or ubuntu folder (depends on the version of wubi, it's been a while since I used it).
You can boot the system with an Ubuntu live CD/USB, access the windows partition from the Ubuntu live system, it should be one of the accessible filesystems on the launcher.
In the Windows filesystem find the Ubuntu "drive" file under program files, and then do the following in the terminal (ctrl+alt+t launches a terminal):
sudo mkdir /media/wubi
sudo mount -o loop,ro /path/to/ubuntu/file /media/wubi
Replace the "/path/to/ubuntu/file" with the location of the "drive" file.
Now you should be able to see a filesystem that is your Ubuntu drive and can copy/upload/email whatever you want from it.
Keep in mind, that your Windows filesystem may be read only on a 12.04 live system, and that by following my instructions, the Ubuntu filesystem is also read-only.