hi Guys, im a New B and need help with my Sat Nav

i have the MK4 sat nav and need help with upgrading it. i know there are plenty of disscusions on this in the forums but i cant get any of them right.

i would like to know the following:

1: my current OS version is SW 4-1/91: is that the latest and if now how do i update it
2: if it is updated to the latest version, what are the PRO's to that?
3: i currently have the 08/2 Navteq road map disk, where can i get the latest one?

thank you for taking time to read this post and hope to hear from someone soon

god bless