[XGh0stz]

Alright, let's just start with the 4 borders, which you only have 3 currently...

I see you have a starting X and also a ending X, but you only have 1 Y...
You need to have that 2nd Y Position...

+++++ <- Y Position
+ +
+ +
+++++ <- Y Postion ( You only have one Y Position when you should have 2! )

^ ^
| |

X X

P P
o o
s s

An example of what you need:
if ( X >= 500 && X<= 600 && Y >= 500 && Y <= 600 ) // Notice you have 4 borders here defining your area, you need to get the other Y Position for your code

The Z cord isnt important, you may remove it if you want