Alfons, You cover a lot of issues, not the least of which is whether or not you have a tax liability at all. (From your post, it isn't clear that you have any tax problem.)

I believe there is a lot of FUD (fear, uncertainty & doubt) being spread; US tax law and reporting requirements have not changed substantially in recent years. So, first constructive suggestion: don't panic. Secondly, be sure you need an attorney (an accountant might be a lot more plausible); they are expensive, in every country.

However, to focus on your question: place a call to this IRS hotline +1 215 516 4777 to ask for details, or just call the US Embassy in Bern (which will have IRS staff somewhere onsite). AFAIK, the hotline will answer your queries without asking for your identification (but if not, you could have a local accountant or attorney make the call).

Please post or PM if any of this is not clear, or did not answer your query.

Further reading (from a quick Google search):
IRS voluntary disclosure practice
IRS FAQ on the current 'amnesty'
Further links from an attorney's website