PowerShell script to control display settings

I need some expert advise on a powershell script that I have that changes the primary screen resolution to the inputed value. This script works fine but I need help expanding the capabilites such as control a second screen. Even if I have to create a second script for the second screen that is fine but I am having a problem finding the right variables to control the other screen.

Current Statement:
[Resolution.PrmaryScreenResolution]::ChangeResolution($width,$height)

I also would like to see if anyone knows the code to change the display setting from extended to duplicate (mirror) displays. - (Windows 7)

Here is my working powershell code so far:

param (
[Parameter(Mandatory=$true,
           Position = 0)]
[int]
$Width,

[Parameter(Mandatory=$true,
           Position = 1)]
[int]
$Height
)

$pinvokeCode = @"

using System;
using System.Runtime.InteropServices;

namespace Resolution
{

    [StructLayout(LayoutKind.Sequential)]
    public struct DEVMODE1
    {
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
        public string dmDeviceName;
        public short dmSpecVersion;
        public short dmDriverVersion;
        public short dmSize;
        public short dmDriverExtra;
        public int dmFields;

        public short dmOrientation;
        public short dmPaperSize;
        public short dmPaperLength;
        public short dmPaperWidth;

        public short dmScale;
        public short dmCopies;
        public short dmDefaultSource;
        public short dmPrintQuality;
        public short dmColor;
        public short dmDuplex;
        public short dmYResolution;
        public short dmTTOption;
        public short dmCollate;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
        public string dmFormName;
        public short dmLogPixels;
        public short dmBitsPerPel;
        public int dmPelsWidth;
        public int dmPelsHeight;

        public int dmDisplayFlags;
        public int dmDisplayFrequency;

        public int dmICMMethod;
        public int dmICMIntent;
        public int dmMediaType;
        public int dmDitherType;
        public int dmReserved1;
        public int dmReserved2;

        public int dmPanningWidth;
        public int dmPanningHeight;
    };



    class User_32
    {
        [DllImport("user32.dll")]
        public static extern int EnumDisplaySettings(string deviceName, int modeNum, ref DEVMODE1 devMode);
        [DllImport("user32.dll")]
        public static extern int ChangeDisplaySettings(ref DEVMODE1 devMode, int flags);

        public const int ENUM_CURRENT_SETTINGS = -1;
        public const int CDS_UPDATEREGISTRY = 0x01;
        public const int CDS_TEST = 0x02;
        public const int DISP_CHANGE_SUCCESSFUL = 0;
        public const int DISP_CHANGE_RESTART = 1;
        public const int DISP_CHANGE_FAILED = -1;
    }



    public class PrmaryScreenResolution
    {
        static public string ChangeResolution(int width, int height)
        {

            DEVMODE1 dm = GetDevMode1();

            if (0 != User_32.EnumDisplaySettings(null, User_32.ENUM_CURRENT_SETTINGS, ref dm))
            {

                dm.dmPelsWidth = width;
                dm.dmPelsHeight = height;

                int iRet = User_32.ChangeDisplaySettings(ref dm, User_32.CDS_TEST);

                if (iRet == User_32.DISP_CHANGE_FAILED)
                {
                    return "Unable To Process Your Request. Sorry For This Inconvenience.";
                }
                else
                {
                    iRet = User_32.ChangeDisplaySettings(ref dm, User_32.CDS_UPDATEREGISTRY);
                    switch (iRet)
                    {
                        case User_32.DISP_CHANGE_SUCCESSFUL:
                            {
                                return "Success";
                            }
                        case User_32.DISP_CHANGE_RESTART:
                            {
                                return "You Need To Reboot For The Change To Happen.\n If You Feel Any Problem After Rebooting Your Machine\nThen Try To Change Resolution In Safe Mode.";
                            }
                        default:
                            {
                                return "Failed To Change The Resolution";
                            }
                    }

                }


            }
            else
            {
                return "Failed To Change The Resolution.";
            }
        }

        private static DEVMODE1 GetDevMode1()
        {
            DEVMODE1 dm = new DEVMODE1();
            dm.dmDeviceName = new String(new char[32]);
            dm.dmFormName = new String(new char[32]);
            dm.dmSize = (short)Marshal.SizeOf(dm);
            return dm;
        }
    }
}

"@

Add-Type $pinvokeCode -ErrorAction SilentlyContinue
[Resolution.PrmaryScreenResolution]::ChangeResolution($width,$height)

Select allOpen in new window

I would appreciate any advise or tips, thanks!