Help - External Clock Source

I'm using SONAR 3.11 with a MOTU 828 and a MOTO 2408.

When I recorded I was using the 2408 as the external (48K) clock source for the 828 and then SONAR but I made the mistake of setting SONAR at 44.1k. Now when I mix down SONAR thinks the audio files are all 44.1k so the result is slow. ie 48k played at 44.1k . I have already done substantial editing of the mix so I would rather not change the individual audio files. Is there a simple way I can fix this? I was thinking that if I mix down at 48k and then get hold of a tool that can change the properties of the WAV file to play at 44.1k then it would be sweet.