[Hampshire] Gtk+

Can anyone enlighten me out of my general Linux ignorance?

I've bought a Canon multifunction scanner. Managed to install the drivers (from
the Canon download site) for printing which works (!). I am now trying to get
the scanner part to work. The documentation says:

REQUIREMENTS
    You need automake and autoconf to build these programs.
    * automake                (1.9.5 or above)
    * autoconf                (2.59  or above)

    You need the following libraries.
    * Gtk+         (2.6    or above)
    * libgimp      (2.0    or above)
    * libdl        (2.0    or above)
    * libpng       (1.2.8  or above)
    * libusb       (0.1.12 or above)
    * libcncpcmcm  (1.0.0  or above)
    * libcncpmsimg (1.0.0  or above)
    * libcncpmslld (1.0.0  or above)
    * libcncpmsui  (1.0.0  or above)
    * libcncpnet   (1.1.0  or above)

Which I'm planning to look for using the Synaptic Package manger.
Can anyone answer these:
1) If I'm running Gnome/Debian/Mint then is Gtk+ already part of the system? It
appears to be a whole shed load of libraries.
2) When it says "or above" in the er.. above then is it best to take the latest
library, or to grab the library that is the same or slightly higher that the
version number?

Thanks to anyone who can help.
Ben.