You really do need to contact the appropriate authorities to get chapter and verse on this rather than relying on the advice of strangers on a travel forum. In reality, what anyone thinks here will carry no weight with the immigration authorities.
Visitor visas are granted for 90 days and allow you to enter the Republic of Ireland once. As far as we know if you do plan to leave the country and then re-enter, you will need to apply for a re-entry visa before you leave. Overstaying is likely to get you into a lot of trouble now and into the future and we'd strongly advise you to contact INIS for advice before taking any action such as leaving the country for a few days with a view to re-entering. You might find it difficult to convince immigration officials at Irish ports (who ultimately will make the decision to land you or refuse you entry regardless of what visas you have in your possession) of your intentions, given the fact that you have already been issued with a year long working visa and a subsequent holiday visa.
Whatever you decide to do, allow yourself plenty of time to sort it out as the necessary processes can take time so don't leave things to the last minute and hope for the best.
This link has contact details for INIS, the Irish Naturalisation and Immigration Service: