Dear Mehdi, Welcome to RepRap.
You posted a good question to the FAQ -- FAQ#Where I can Find all I need to rebuild my own Reprap?. I hope the answer will appear there soon. :-).
You may also want to check the General FAQ.
The current RepRap documentation is still a bit confusing and disorganized. Please help us make better documentation.
--DavidCary 16:49, 29 December 2010 (UTC)