im guessing this subject has been asked about a million times so sorry

got a 52 plate 3.0d sport, i reckon its the original satnav disc in it, so i want to know how to upgrade it cheaply if possible!
the disc says 2002 - 2 on it, its a navtec? disc, theres no postcode facility on it either, and the graphics are a bit blocky
so, can i get a disc that will upgrade it?? or am i looking at a hardware/player upgrade as well??
while im on the subject, my telly is of course analogue, and as im in Wales im digital here so telly dosnt work here(altho it works fine in england as i found out at the weekend)
so whats the cheapest/easiest option for upgrading to digital? i know i prob wont use the telly that much but id like it to work,
these are prob the first of a few questions guys, bear with me please

oh and one more

thanks in advance guys,
John