This website below briefly offers some tips for driving in Ireland. Although the article mentions renting a manual car, you can request an automatic for a slightly higher rental fee (if not really experienced with a stick shift, this is recommended). It is also recommended to get full coverage...better safe than sorry on the narrow roads!
http://goireland.about.com/od/touringireland/tp/to...
Stay on the left side!
Only drive clockwise through a roundabout!
Watch out for crossing animals if driving in the countryside (not kidding!)
There are also some videos on youtube that may be useful as well. It helps to see a car in action!
There are no "cops" that will pull you over for speeding but there are "speed vans" parked along the roadways occasionally that take a picture of your license plate if speeding (similar to a camera at a red light in the US). Fines are typically low when compared to speeding tickets in the US but it is best to avoid them!
Have some change handy incase you end up on a toll road (probably a necessity at some point in your travels). Most have barriers where you stop and pay but not on the M50 (you just drive right through but must pay online). If you end up on the M50, go to this website by 8 pm the following day to pay your toll. It is simple to do but easy to forget.
The currency for the Republic of Ireland is the Euro (Northern Ireland is the pound but you most likely won't be there!)
You can exchange your current money for Euros at the airports, Ireland banks and local ATM machines. It is much cheaper to do so in the US before you leave (exchange rate has a lower percentage). Try to estimate how much you might need to avoiding having to pay the fee all over again once you get back and need to convert what you did not use. While the Dublin area is reasonably well served with ATMs, the same can't be said for smaller towns and villages where there may be at most one ATM in the locality.
Acceptance of Visa and MasterCard is almost universal for retailing and most services, including supermarkets, accommodation, railways, restaurants, gas stations, department stores, payment of parking tickets, airport parking charges, etc. American Express and Diners Club cards are also accepted by some service establishments. Very few if any establishments accept the Discover Card.
If interested in the dollar to euro conversion, you can use this website.
http://www.xe.com/pca/input.php?FromSelect=USD&ToS...Be sure to bring an adapter (to charge your cell phone) and possibly a converter for other items (some hairdryers, electric razors, etc.) Below are some helpful hints to help you decide what you need (adapter vs. converter) to bring.
The electrical supply in Ireland is 230v 50hz. The plugs and sockets are different from the USA involving a three-pronged formation, the same as those used in the United Kingdom. If your appliances operate on a different current (such as those from North America) you will need a power converter and plug adapter.
A plug adaptor does not change the electricity supplied to the appliance, only allows it to be plugged into a different type of wall socket. If the appliance you are using supports dual voltage and dual frequency then a plate/tag will be located on the item stating "120/240v, 50/60Hz".
Most laptop computer and battery chargers are dual voltage, so all you will need to use them with a different supply is a plug adaptor.
Power converters step down the voltage from 240v to 120v, allowing equipment which is not dual voltage to operate at the voltage for which it was designed. Converters do not alter the frequency at which electicity is delivered and should be used a maximum of 1-2 hours at a time.
Converters can be purchased at travel stores, some discount stores, office supply stores, and electronics stores. Make sure that you select a converter that will accommodate the wattage of the appliances you wish to operate. Some laptop computers, electric razors and hair dryers have built-in power converters. However, an adapter plug will be required.
Here is another website that may also help:
https://www.rei.com/learn/expert-advice/world-electricity-guide.html