Zombie Wave Spawning Script help?

Hello, im a novice at coding, and am needing a little help with waves of zombies spawning in my scene. So i have multiple spawn points in my scene and i want on wave 1 for example to spawn 5 zombies, but i want them to spawn at the spawn points randomly, maybe 2 spawning at one point and 1 at another ect… And i have an audio sound that i would like to play when the wave is complete. Below are some of my variables, if anyone can help it would be much appreciated.

var zombiePrefab : GameObject;
var zombiesSpawned : int;
var spawnPointOne : GameObject;
var spawnPointTwo : GameObject;
var spawnPointThree : GameObject;
var spawnPointFour : GameObject;
var spawnPointFive : GameObject;
var spawnPointSix : GameObject;
var spawnPointSeven : GameObject;
var spawnPointEight : GameObject;
var spawnPointNine : GameObject;
var spawnPointTen : GameObject;

I wrote a free example on another forum, you check it out here:

Demo: https://dl.dropboxusercontent.com/u/84339701/Showcase/SpawnProject/SpawnProject.html

Play till level 10 to see the full potential.