Click any of the db using custom to export.
When you are importing db ,we must create a new db and then import the backup sql file .
But we can change the size .Go to :
You need to search for these locations:
memory_limit = post_max_size = upload_max_filesize = change the desired value you want. After that see below Note : when you are moving one server to another server .Please note the db name ,username ,password etc. and also ensure the data s for that db .