This Irish Times article gives very graphic details of the actual offenses, and makes it clear that Walsh had at least one criminal conviction in the 1990s. Apparently, he fought the more recent criminal trial for some eight years, but lost his fight. I hope he was in jail during those eight years, but maybe that's too much to hope for. Still, the fact of the matter is that the church dealt with the matter in 1990, and the Garda in 1995. What's happened since, is merely the time that it takes for judicial procedures to progress.
As Smokey says, the recent conviction was for offenses that took place "during the late 1970s to the early 1980s" - the same offenses that got him removed from the ministry in 1990 and began the police prosecution effort in 1995. Has he been in police custody since 1995?

-Joe Offer-