you should be able to get that derailleur at the bike shop pretty cheap. That chain doesn't look right though. Maybe get the lbs to lay a new campy chain in there when you are buying your front d. If it doesn't slip down like the shimano one, buy the chain too.

My guess is the campy chain won't work with the Shimano cassette next. But don't worry, I think Action Tec makes a Titanium Shimano freehub body to Campy index spacing cassette for like 856 bucks. I think the mechanic that told you everything would work together just fine lied to you.