Here's another option for the .wma files. Choose
Export from File menu of QuickTime Pro (Command E), select AIFF as file type. Then add it to iTunes.
As an AIFF file it is lossless and will not lose any more quality. After adding to iTunes, unless you are hard disk short on space, keep it as AIFF else convert to apple lossless which is a lossless compressed format. Other formats such as mp3 and m4a will result in some loss of quality of the file.
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