Hi,
I don't have access to marriage records - pre 1864 is difficult if your relatives were Catholic - you would have to go through parish records. However, I have had a bit of a look round to see if there is anything you could do.
1) You could search in Family Search using Michael and Margaret as parents. This turns up 3 children between 1860 and 1866 (sadly all with different Margaret mothers!) but you may know of one of the children. If the 1866 child was yours- you could apply for a birth certificate.
2) Collooney seems to have been in the parish of Ballysadare for Griffiths Valuation - again by searching here;
www.failteromhat.com and then Griffiths index you can find Killgallen in Ballysadare parish - not Collooney townland but 2 other townlands. Using this you can cross reference with the mother surnames - 1 at least is in the parish - in Collooney in fact.
3) Lastly, there is a website which covers present day Collooney- parish is Kilvarnet now. There is an email address - might be worth a try - someone may have access to parish records there. I can't copy the address but browsing for Collooney (Kilvarnet) Parish will get you there.
Best wishes
Heywood
