In such a short time, I think you should stay in Dublin or its close environs.
Firstly, The Mespil Hotel is on the canal beside Baggot street. There are a few nice bars and restaurants if you turn right from the canal onto Baggot st. a 3 minute walk from your hotel.
A ten minute walk from the hotel, turning left over Baggot st. bridge is a pleasant walk past georgian buildings to St.Stephens green. There are some nice restaurants and pubs on Dawson st. and off Grafton st.
Alternatively a short taxi drive in the evening will get you pretty much anywhere in the city for drinks/dinner.

As for friday, You could start at Trinity College and see the Book of Kells, then a 3 minute stroll down College Green (past the old parliament building,now a bank) to Dublin Castle and City Hall.
From there you could walk or bus it the short distance to Guinness and Kilmainham Gaol. This would take all day allowing for lunch stops etc. It might be even better spread over the two days taking things slowly.

If you do all the above in a day, then on saturday you could think about a daytrip out to Howth (north dublin) or Powerscourt/ Enniskerry in county Wicklow.
Enjoy the trip