I have a TomTom 710 (the higher the number the more countries that come pre loaded) and I'm quite happy with it.
We rented a car for one day to move everything from our apartment in the city centre to Tres Cantos from Europa Car and they offered a Nav for 7 euros a day, money well spent, would never have gotten around Madrid if we had tried maps!
If you only need it for limited time see if you can rent one from them.
And yes Nav systems are portable, you can even use them for walking around a strange city. I put mine in my back pack and it turned it's self on and all of sudden I heard "turn left in 50 mtrs"
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Be Canadian Eh, that's for all you American out there:)