Beautiful bike - congratulations. The Roma Olympiade was Legnano's top model in the 60's, and in the classic green it's very iconic. I think your dating based on the components is probably accurate - 1963 to 1967 or so. Which means you don't need the first-generation Campagnolo cranks that cost a mint, but you will ned the 151 bcd cranks that can still be pretty expensive, especially if you are looking for a set that is as nice as the rest of that bike. Think $150 (if you're lucky) to $200+ in excellent condition. Here's a pic of a similarly equipped bike with the cirrect crankset:

http://www.classicrendezvous.com/Ita...no_M_Barry.htm