How do I stop sprite animation on last frame?

Hi there, I have been using this script to animate a sprite sheet and I was wondering... How would I pause the animation on the last frame? I'm trying to do this for a falling animation. I've tried everything I can think of and spent hours trying to solve this myself. Can anyone out there help me out a bit? Thanks in advance for any answer provided!

Code:

 function aniSprite (columnSize, rowSize, colFrameStart, rowFrameStart, totalFrames, framesPerSecond){
 
     var index : int = Time.time * framesPerSecond;                                                    // time control fps
     index = index % totalFrames;                                                                    // modulate to total number of frames
     
     var size = Vector2 ( 1.0 / columnSize, 1.0 / rowSize);                                            // scale for column and row size
     
     var u = index % columnSize;                                                                        // u gets current x coordinate from column size
     var v = index / columnSize;                                                                        // v gets current y coordinate by dividing by column size
     
     var offset = Vector2 ((u + colFrameStart) * size.x,(1.0 - size.y) - (v + rowFrameStart) * size.y); // offset equals column and row
     
     GetComponent(Renderer).material.mainTextureOffset = offset;                                                    // texture offset for diffuse map
     GetComponent(Renderer).material.mainTextureScale  = size;                                                    // texture scale  for diffuse map    
     }