To get accented letters on a PC, type the appropriate extended ASCII code on the keyboard's number pad while holding down the alt key. í is alt161; ú is alt163. I'll put a larger list under diacritics.
I hope it's not rude to point this out, but scriobhfadh doesn't mean quite what you think it does, I suspect. The word for "author" in the poem on the link is "udar". scriobhfadh is a form of the verb "scriobh", to write: specifically it is the 3rd person singular of the conditional, i.e. it means "would write".
The "u" in "udar" and the "i" in "scriobh" and "scriobhfadh" need accents, but I don't know how to make them.
on edit: this comment applies to its inclusion on reesetee's list