After searching and searching I found the following site which will allow you to get tickets to a Papal Audience. I hope you find this of use if you are going to be in Rome this year.
On most Wednesday you can attend the public audience in St Peters Square in front of St Peters Basilica. You can request the tickets by email and there is no charge. You will be directed to the web site to St Patrick’s American Community in Rome. All the information you will need can be found on this page.
Once you are on the page, the ticket link is on the right side of the page. Allow two to three weeks for a response. You must pick up your tickets in Rome the day before the audience.
Here is a copy of the reply I received for my request:
The St. Patrick’s Catholic American Community of Rome is happy to assist you with 2 tickets for the Pope’s General Audience on Wednesday September 13, 2017 at 10:00 AM in St. Peter’s Square – Vatican City. While the Pope begins his presentation at 10:00, the gates open at 8:00 and the seating fills up quickly. We strongly recommend arriving early. The audience usually lasts for one hour. Please check www.vatican.va under info/Prefecture for any change in the program.
Reserved Tickets can be picked up on Tuesday afternoon, September 12, 2017 between 4:30 and 6:30 PM ONLY in the Foyer/Sacristy of the Church of St. Patrick (San Patrizio a Villa Ludovisi), Via Boncompagni, N. 31 (near the corner of Via Boncompagni and Via Piemonte) near the US Embassy and the Via Veneto. The Church itself will open at 4:00 PM, and you are welcome to come inside. However, we do not begin the distribution of tickets until 4:30 PM. And if you would like to stay and join us, our weekday Mass in English at St. Patrick’s is at 6:00 PM.
If you are unable to pick up your tickets on Tuesday afternoon, on Wednesday morning between 7:30 and 8:30 AM you can go to the Bronze Doors – St. Peter’s Square – Vatican City – and ask the Swiss Guards for tickets to attend the General Audience.
Please Note: The tickets are Free of Charge, but we ask you to consider making a free will offering of 5 Euros or 5 U.S. Dollars per ticket so that we can continue to offer this service.
Saint Peters Basilica, Rome