Display text while close to an object

So I wrote a script that draws a texture on Screen when being close to a certain object. Now I’d like to display a little text when being close to this object to show which button to use to draw the texture. What do I add to my code to make that work?

using UnityEngine;
using System.Collections;

public class karte : MonoBehaviour {

	bool map = false;
	public Texture MapDummy;

	// Use this for initialization
	void Start () {

	// Update is called once per frame
	void Update () {

		GameObject go = GameObject.FindGameObjectWithTag ("Player"); 
		RaycastHit hit;
		Ray landingRay = new Ray (go.transform.position, Vector3.forward);

		if (Physics.Raycast (landingRay, out hit, 10)) {
			if (hit.collider.tag == "PC") {

				if (Input.GetKeyDown (KeyCode.O)) {
					map = true;
				} else if (Input.GetKeyUp (KeyCode.O)) 
					map = false;
	void OnGUI () {
		if (map == true) {
			GUI.DrawTexture (new Rect (0, 0, Screen.width, Screen.height), MapDummy);

you can use sphere overlap Sphere overlap

you can set a dimeter if any object with collider comes in range with that dimeter can be tracked