Thank you for your post to the Ireland Reaching Out message board.
I do not see St. Martin's graveyard on the Historic Graves website as having been recorded and transcribed. I also do not see where it has been transcribed or any headstones recorded on other sites such as wwwfailteromhat.com, www.interment.net or the Cork City and County Archives. However, we do have a few volunteers in the general area and I have forwarded this query to one of them. You should expect a reply in the next week or two and hopefully someone may have some information.
The very best of luck with your research!