Does unit have external SD? If not, then you will have to overwrite internal storage to replace maps. If there is external SD, you might be able to leave internal storage alone and tell iGO8 to read maps from external SD. Latest HERE Europe map is 4GB [Only registered and activated users can see links. ] so you will have to pick countries that you need.

P.S. as I have said before, it's not 2GB of memory you have, it's 2GB of storage. Use memory to indicate RAM and storage to indicate diskspace. BTW, what do you use bluetooth for?