Spawning Gameobject in Grid (x-axis)

I’m attempting to spawn a gameobject along the x axis of my grid in random locations (0-7) along the 7th row of the y axis. I’ve been racking my brain for several days trying to get this to work and I have been unsuccessful. I’m looking for help on how to solve this problem. Here is my code for my grid.
public GameObject gridPiece;
public int Width = 10;
public int Height = 10;

	//private GameObject [,] grid = new GameObject[10,10]; Didn't contribute to array code.

	void Awake () 
		for (int x = 0; x < Width; x++)
			for (int y = 0; y < Height; y++)
			{GameObject grid = (GameObject)Instantiate(gridPiece);
				grid.transform.position = new Vector2(gridPiece.transform.position.x +x,
				                                           gridPiece.transform.position.y +y);
				grid.transform.parent = gameObject.transform;


Here is the code I have for my spawner.

//Random Block Spawner
	void SpawnRandomObject(){
		int whichItem = Random.Range (0, 4);
			GameObject myblock = Instantiate (enemySet1[whichItem]) as GameObject;
				myblock.transform.position = transform.position;



to create a random number than create new position with it

void SpawnRandomObject() {
    int whichItem = Random.Range(0,4);
    GameObject myblock = Instantiate(enemySet1[whichItem]) as GameObject;

    float x = (float)Random.Range(0,7);
    // Use 6 for y axis if you want it on the 7th row (since your first grid object was created at 0
    Vector2 newPosition = (x, 6);
    myblock.transform.position = newPosition;