I want the RSSI data to be shown on my computer.
Why?
The problem is that I can't run my code that shows the incoming data on my Computer when I have the XBee connected to the Arduino because I have to remove the microcontroller when using XBee.
Sniff. Sniff. I think you stepped in something that smells a lot like bullshit.
Ditch try to talk to the XBee using X-CTU and just open the Serial Monitor.