You should contact the Secretary, St. Mary's and St. Michael's church in New Ross to ascertain if the school is still in operation. Email: firstname.lastname@example.org. From checking the web, it appears that it is! The principal will be able to tell you if the records for 1890-1900 are in the school. If not, you will need to make arrangements with the National Archives - www.nationalarchives.ie in Dublin. If you are unable to view the records yourself, you will need to engage a researcher. They will advise you.
Due to Covid19 virus it is going to be a slow process.