How to make resolution not go less than 1280x720?

Alright people, I need some help with this please :P

So I have this script which changes the resolution of the game. It´s like a popup list done in NGUI. Everything is cool and works, shows all the resolutions your pc could have. Now my problem is that: I don´t want the player to go less than 1280x720 in resolution, because that would screw up some important UI in game which can´t be fixed because I´ve been stupid enough to just make it NOT below 1280x720...

Here´s my script (written in C#):

 using UnityEngine;
 using System.Collections;
 
 public class ScreenResolutionChange : MonoBehaviour {
     public bool isFullscreen = true;
 
     private UIPopupList popupList;
     private Resolution[] resolutions;
     private string[] resolutionMenuText;
     public string selectedWidth;
     public string selectedHeight;
     public int HeightTeller;
     
     void Start() {
         popupList = GetComponent<UIPopupList>();
         resolutions = Screen.resolutions;
         resolutionMenuText = new string[resolutions.Length];
         popupList.items.Clear();
             
         for(int i = 0; i < resolutions.Length; i++) {
             resolutionMenuText[i] = resolutions[i].width.ToString() + "x" + resolutions[i].height.ToString();
             if(resolutionMenuText[i] != "1280x720") {
                 popupList.items.Add(resolutionMenuText[i]);
             }
                 
             if(resolutionMenuText[i] == Screen.currentResolution.width.ToString() + "x" + Screen.currentResolution.height.ToString()) {
                 popupList.selection = resolutionMenuText[i];
             }
         }
     }
     
     void Update() {
         string[] splitter = {"x"};
         string[] curDimensions = popupList.selection.Split(splitter, System.StringSplitOptions.None);
         
         if(curDimensions.Length == 2) {
             selectedWidth = curDimensions[0];
             selectedHeight = curDimensions[1];
         }
         
         HeightTeller = int.Parse(selectedHeight);
         
     }
     
     public void ApplyChanges() {
         if((selectedWidth + "x" + selectedHeight) != (Screen.currentResolution.width.ToString() + "x" + Screen.currentResolution.height.ToString())) {
             int w = int.Parse(selectedWidth);
             int h = int.Parse(selectedHeight);
             Screen.SetResolution(w, h, isFullscreen);
         }
     }
 } 

Thanks in advance smart people :D