Audio using XML and Flash

I really want to remote access audio in Flash. I believe the best way to do this is via XML (correct me if I am wrong)…? Essentially here is what I want to do:

I want to have a button that is on my site, when someone clicks it, it will read the text. I DO NOT want to make my flash file bigger it is at 4.2mb already… I have a XML/flash Album w/ thumbs and I have another area that has categories that open up with text, this is where I want to do the voice reading the text??

Any suggestions on how to do this without using alot of space?