I need both reach GUI features of c# toolboxes and fast rendering features of XNA, is there any way to merge these two into one app? or is there any other way? for example some equivalent to c# toolbox in xna?
I assume you are referring to Windows Forms when you talk about "GUI toolbox". There are two samples available in the App Hub to mix XNA rendering with standard controls:
(but you lose Xbox360/Win7 Phone/Zune compatibility)
If you are looking for a GUI library for XNA, take a look at this post from Stack Exchange.
Here's a couple of video showcasing XNA + Awesomium:
If you are programming for Windows Phone 7, the new Mango update of the OS adds support for XNA games inside a Silverlight application. This way you can create the menus and GUI in Silverlight, and lauch the game inside a frame. It is expected that Microsoft will sometime soon implement this feature on the PC and Xbox360 versions of XNA, but there's nothing official so far.
Check this article: XNA for Silverlight developers