Exciting! I was just in Italy and saw all these awesome, tiny 4x4s and thought they would be great over here. You are ahead of the curve!
I don't know of any Fiat specific mechanics in PDX, sadly. A fellow Fiat buddy has used a mobile mechanic with good success. I will PM you the contact info.
I also am not aware of any specific Fiat clubs. Seems we should start one.