Back up save files

Just wondering, can I backup my save files from no$gba for NDS games? (Cos I played and the game crashed and my save file was gone so I don't wish to restart all over again if it happens the next time) Will copying an extra folder of the contents in "Battery" folder work?

I'm also considering to buy a real DS. Are they able to link cable/trade with GBA? Cos I have a GBA. If I insert a GBA cartriage into the DSL, am I able to trade with another playing playing GBA on DSL? Thanks for answering!