Josephine, I don't know if there is an easy answer or indeed any answer to your question about where to find Peter's parents. If he was born before 1831 then you obviously need to find his baptism in a parish whose records cover that date. Using the Irish Times link which Gaffy provided, you can click on each of the close-by parishes to see what records they have. The earliest ones date from 1835. I have already had a look in Kinally/Kinawley without success. I cannot be certain that I did not miss a Hackett record but I did not spot the name even once there and in my experience names tend to repeat themselves regularly.
In these situations I tend to burrow away at records which might be relevant and hope that something might emerge to make a link. As you know there are Hacketts in Griffith's Valuation not too far away. I can also see some in Tulleyclay (now Tullyclea) in the 1821 census fragments which are now on the main census site. There is also a Hackett in the census search forms which were used to verify the age of pension applicants:
http://censussearchforms.nationalarchives.ie/search/cs/home.jspAnother thing to consider is the Irish naming pattern which was used by many families to select the names of children. There are a few versions of this but most I think say that the first son was to be named after the father's father and the second son after the mother's father. The first daughter was to be named after the mother's mother and the second after the father's mother (and there is much more to it for later children). If I have it correctly the Hackett daughters' names reversed this order but often there was a reason for deviating from the norm. So if James was the first son and John the second (the name of the mother's father) then there is a reasonable chance that James was the name of Peter's father. However you cannot ever use this with certainty.