Mully, you can leave your PC in the lounge and use the XBOX to have a MCE in your bedroom, or any other room in your house.
Basically, you can have the PC anywhere and the XBOX anywhere as long as there is a decent network connection between the 2.
Obviously if your MCE is currently setup in your lounge, I wouldn't move it.
In the past I have used the XBOX extender and currently I use the XBOX 360 MCE extender and they have both worked beautifully!
Shout if you need any other advice.
Thanks
Chris