Importing 40 gb mysql file via phpmyadmin
If you really want to restore it with PHPmyadmin you have to split the files into little chunks, because PHP will block too large files, depending on the serverconfig.


Dump just the structure of your tables
Import them
Dump the data of your tables into a csv
split the csv (on windows you can do this with gsplit for example and on unix with the split command
Import the little chunks of data


But in general i'll recommend the commandline or contact your ISP