Brain Buster: Music Video

Me and a friend are making a music video. We are using swift3d and Flash. We have come across a slight problem though, that i have NO idea what to do about.

Our song is fairly large. 8 megabytes. We plan to submit it to Newgrounds, and have it available for those that may not have a great connection. We were thinking around 4 -5 mb. Want we want to avoid is having horrible sound quality. SO we streamed it from a server on the web, that works fine. BUT chances are if our animation lags on someones computer, the music will NOT lag, thus making them completeley out of synch. And with our project synchronization is everything. If there is ANY way to :

Have Great sound quality
Have it synched
And have a 4-5 megabyte file (including animation)

Please, tell us.
Thanks very much
-Adam