Download DAA Converter. Double-click the downloaded .dmg file to mount it, then drag the DAA Converter icon from the window that comes up, into your Applications folder.
Open DAA Converter and select the file you need to convert. Click Open and it will convert your .daa file to a .iso file. ISO files can be burnt to discs, or files can be extracted from them. Follow the next step to extract the files from ISO file, which is what you would most likely want.
Double-click the .iso file, which will be in the same location as the original .daa file. It will mount. In Finder, you can find it under Devices. Click on the mounted .iso file and you can get the files.
If you have doubts about any of these steps, leave a comment (scroll down to the end of this page) and I’ll try to help.