I have had good luck with the correct parts at reasonable prices from Bertlesbeck in Germany. Their website is Alfa Romeo Parts & Alfa Romeo Tuning
and when you order, they will send an email for confirmation. The confirmation will show your price without the German VAT and their rates for Fedex shipping to the US are very reasonable. They seem to keep most parts in inventory especially for the older cars that were common in Europe but are very few and far between here in the USA.