if this plus that is greater than zero

Easy noob question: I would like to know how I can get this if statement to work. I want it to do something if this plus that is greater than zero, but it tells me that -= is an unexpected symbol. Here is the code:

if (GameObject.Find("Count").GetComponent(Values).highValue -= myFloat >=0){

highValue is a variable of the script Values. I want to subtract myFloat from that number so that the highValue becomes a low value. Basically, my condition is that in order to do something, my highValue - myFloat must be greater than zero. My code is an extension of what is going on here: http://unity3d.com/learn/tutorials/modules/beginner/scripting/if-statements

if (GameObject.Find(“Count”).GetComponent().highValue - myFloat >=0 ){

This is an addition to what richyrich said. Would this work?

GameObject count = GameObject.Find("Count");
Values valueScript = (Values)count.GetComponent("Values");
valueScript.highValue -= myFloat;


if(valueScript.highValue > 0) {
	//Code here!
}

I’m a bit of a noob myself, but let’s hope it works, haha!