Can I suggest that you visit www.irishgenealogy.ie which is a free Irish government site which has RC church records for the Diocese of Cork and Ross. I believe the parish you want is Rossalettiri and Kilkeraunmor (Roscarbery and Lisseyard) There are many Donovans in that area and many Mary Donovan baptismal records. I located one for 1844 for a Mary born to Timothy Donovan and Ellen Malone. There could be other possible records for a Mary with a father Timothy.
Let me know if you have any questions.