You only need to put a new Europe map on your device...the latest is 880.xxxx
Firstly you need to find out what navcore (TomTom operating system) you have on your device and what features it supports....then how much drive space your TomTom has.
Once you know that, you can look at an 880.xxxx chart to find out which map with what features suits your device. Some Europe maps might be bigger than your device can handle for example. When you've figured that out, you'll be able to search and download a map that is listed in the 'sticky threads' in this forum.
If you don't know what you're doing then I recommend you download an 'Auto-Activating' map which will do all of the work for you in relation to patching etc.
MAKE SURE YOU BACKUP YOUR TOMTOM WITH WINDOWS EXPLORER (SHOWING ALL FILES) BEFORE YOU MAKE
ANY CHANGES TO IT IN CASE YOU MAKE A MISTAKE AND NEED TO RESTORE IT - IF YOU MISS THIS STEP, THEN YOU ONLY HAVE YOURSELF TO BLAME!!!!
I hope that helps