I updated from an iPhone 3G to an iPhone 4S approximately mid-December. I had some voicemails from earlier in 2011 that I had to keep for legal use. I just noticed when I tried to reference them that they are no longer listed on my iPhone. I know I never deleted them and when calling into AT&T for my voicemail I think they are all still there but it's hard to sort through them plus it's hard to play them/record them for someone else. The only thing I can think of is these voicemails were left before I upgraded to the iPhone 4S and I have a lot of voicemails on my iPhone but believe they are all post-iPhone 4S. I don't know why the upgrade caused my iPhone not to display these older voicemails and I may be wrong but I believe that is the cause of this.
Assuming I'm correct with the above, how can I get access on my iPhone to the earlier voicemails before I upgrade to the 4S?
Assuming I can get to these voicemails I have another question. The person I need to send these two wants them in Windows Media format. Is there a way I can do this? Is there an app that would convert voicemails to this format? Assuming I can't do it that way is there a good voice recorder for the Mac that will take this off of my iphone (using it on speakerphone) and record a Windows media file from it?

Thanks for your help.