When I went to Brazil recently, the bank advised me not to take euros, as I would not get a decent exchange rate, they advised taking dollars. Get your granny, or someone over 65 to get dollars from AIB with no commission fee.
My advice would be to take about $500 US in small notes & store it in a safe place, only use it in an emergency, then top up your credit card and use that & dripfeed it (as mentioned above). Also try bringing a 2nd credit card with you, if you can get someone close to you to get a 2nd card on their a/c.
When you get there, try & avoid banks which charge a withdrawal fee. I found HSBC v. good, and no fee. And find out daily withdrawal limits & closing times, if any. (eg. in Brazil most ATMs shut down from 10pm to about 6am for security reasons)