Post your code in [ code ] tags [ / code ], your more likely to get a reply.
you have three buttons that do nothing when clicked? You also call them button1 button2 button3 which is completely unhelpful to anyone (including yourself) who comes back to this code in a while and wonders what the hell is going on.
You have also pasted your R.java file, this is autogenerated as the comment says so is useless in this context.
If oyu want to play an MP3 there is a perfect example on the developer.android site:http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/media/MediaPlayerDemo_Audio.html