Debian woody kernel

[John W]

  I managed to get the dist upgrade to Woody completed. Xfree86 4.0.3 is 
installed but I cannot get an X display with this Nvidia card (worst 
purchase I've made). I managed to find the debian source for the Nvidia 
kernel patch? and GLX module. I used the simple install method in the 
beginning with potato and it seems I have no kernel headers or source 
installed. How can I determine what kernel is being used and then get the 
appropriate source and headers?

Regards,
John