Need help undeleting a Big gz compressed tar ball

[To Ro <tonroca@gmail.com>]

Where: External SeaGate Drive of 1 TB
I had a Big.tar.gz file (about 400gb) with all the contents of my home directory, in a maze of directories and subdirectories.
After extracting a directory with all its contents from Big.tar.gz to my hard drive, I decided to delete that particular directory. My mistake was to use archive manager from gnome 3 (debian wheezy), insted of using the command line. A wrong click started the deletion of the whole Big.tar.gz
After a few hours, my Big.tar.gz was gone. I tried testdisk, but has not been very succesful. I was able to see and copy to another disk about 18 files of different sizes, from 6 gb to 70 gb, with names such as inode_xxxxx
Running the command "file inode_xxxxx" yields not much, it says data file.
The process of copying by testdisk had to be halted because the target disk was full, and testdisk hung for several hours (night time) before I stopped the whole thing.
What should I do?
(Thanks in advance to all).