I purchased a program that converts music files from one format to another (I had to convert from WMA to MP3). I NEVER rip my music files in AAC, as that is an Apple format and I use my music on different platforms.
You may want to invest in a computer program that converts music files from one format to another. It can be a somewhat time-consuming task. And not all the ID3 Tag information converted properly to the MP3 version (tho, that could just be the program that I used).