OK. things are clearer now.
you need to copy the mp3 files from the data CD to which you burned them back to the hard drive of your computer.
now, start up your Easy CD Creator and start making an Audio CD. dragNdrop the mp3s to the application window, it will add them to the CD compilation you're making, and it should automatically convert them from mp3 format to cda format - cda format is CD Audio, that what can be played on HiFi sets and car audio systems.
hope that helps.
One Ring to rule them all, One Ring to find them,
One Ring to bring them all and in the darkness bind them
In the land of Mordor, where the Shadows lie
M.C. Escher - Reptilien