Irish immigration Q&A: Can my family and I return to the U.S.?
Also bear in mind that when you’re at the embassy you’ll also be able to apply for U.S. passports for the children, which they’ll be needing in order to enter the country.
As for your wife, you’ll have to apply for a new green card on her behalf at the embassy, as the one she used to own is null and void. Be prepared for a wait of several months before her permanent resident status is confirmed, so you should start the process as soon as possible.
The embassy link for more information is http://dublin.usembassy.gov/filing_the_i130.html.
After having her green card for three years, your wife would be eligible to file for U.S. citizenship. She should strongly consider this, just in case your future plans take you back to Ireland, or elsewhere.