Although we can not help with specific genealogical research questions at this time, we can provide some information on some resources that may be useful to you in this area.
For research and organizing your genealogical research Ancestry.com is the industry standard.
Another well established resource is Find A Grave.
GenForum has active forums for discussion on the various MacCarthy names. Here is one for McCarthy. Of course other variations of the name are here as well.
There are some books with plenty of genealogical records that may be hard to obtain or have been otherwise lost:
The McCartys of the Northern Neck, 350 Years of a Virginia Family by William McCarty and Kathleen Much.
If you are new at Genealogy research you may want to read this article, it mentions many of the links above but also provides a generally sound process to approach your research.