How do I get a 3DS save from one SD card to another?

I bought Dual Destinies on one memory card and created a save backup when I deleted it, now I am re downloading it on another memory card. How do I transfer the save backup from one SD card to the other?

on your pc...

you need an sd card reader on your pc...

just copy the data to your hdd...and then to the new sd card...easy

But which data is the save data, its just a bunch of numbers.

oh sorry... you want to back up the save?

doesnt the system save to the actual game cart?

the sd card is just to hold extra games...yea you cant specifally find a game save and back it up...

you have back up the whole card.

I had to do this for my Monster Hunter 3 save. I googled what number that game has, and copied that, which worked. If no one on google say what number the game has, I do not know what to do, other than copy all data..