Version Error

I am using the parameters that GL_BGR in this function:
glReadPixels(0, 0, m_ViewPort.x, m_ViewPort.y, GL_RGB, GL_UNSIGNED_BYTE, GetDocument()->CreateScreenImage(m_ViewPort.x, m_ViewPort.y));

it can not pass compile because that the compiler visual studio has a head file gl.h that is in vision 1.1
I had read about the key words"GL_BGR" is start supported by vision 1.2.
what can I do?
download a gl.h which in vision 1.2 in windows?
I can not find it!

Hi aQ,
Microsoft stop update OpenGL on windows since 1996, the actual version is 1.1, if you want to use latest OpenGL version, use extensions as said on Extension page

hope that helps