It may be a little late, but if you have an external harddrive it is easy to do this. You can clone your Ubuntu partition(or partitions if you have a seprate /home) with fsarchiver, save the backup in the external drive, which doesn't have to be very big, just big enough to store the backup, the file is probably rather small because it is compressed and that since you are out of space the original is probably not very big either. Then wipe Windows and format the drive to ext4, then retsore the image from the external drive to your internal drive and it will save everything. In my case my external drive has already another Linix installed so it is formatted in ext4 already. In general I think you don't need to format it this way, but check the documentations.
Originally Posted by josh17
Install fsarchiver in Ubuntu
sudo apt-get install fsarchiver
Keep in mind that if you are cloning the same Ubuntu that you are running fsarchiver on you have to use the two options "-a" and "-A",
so if you want to clone /dev/sda2 you would need to run something like
Edited: Oops, it seems that you do need to run fasrchiver from a live usb in order to restore the image. I forgot that because l have multiple Linux distos on different drivers and partitions so I am used to running fasrachiver to clone partition A and save to partition B and then restore from B to C etc without thinking..
sudo fsarchiver -a -A -j2 -v savefs /path/to/backup/folder/ububackup.fsa /dev/sda2