"did some research and figured out i needed old database too(.gz file)..(found a backup of it)"
Extract the .gz file on your computer then attempt to import the SQL file using phpMyAdmin. A program like WinRAR can be used to extract .gz files.
The SQL file is plain text. It will be much larger than the .gz file. I have in the past had problems with .gz files so I always save as .zip when I backup a database.