Johan - Dixons stock the software and may be able to help with your questions regarding the Ipaq. Alternatively your welcome to pop down to Milton Keynes and see if my version will work..
As for the gps receiver I would def rec a bluetooth box ( although you still need to wire it up if you do a lot of travelling as the batteries last about 4 - 6 hrs max.)
Personally I went down to London ( Tottenham court road ) to seek out my tom tom and receiver and car kit for a good price.
I rec http://www.pocketgps.co.uk/
for more info and forums n stuff to help.