@Angel89: actually we cannot write whole script for you.
Forum is the way to get some clue how to solve a problem.
You need to understand a more of XML and NSIS to write working script.
If anybody writes script for you and later you change something in xml then you will need to ask on this forum again... that is bad approach
Try to understand the problem and learn NSIS or hire someone to write script for you.
This is only general comment, no offense