Are you aware that the family search website has recently added Slovak records that you can browse through if you know the village/town you ancestor is from check this out for Nove Mesto on the familysearch.org website:

Slovakia, Church and Synagogue Books, 1592-1910
Roman Catholic (Rímsko-katolícká cirkev)
Nové Mesto nad Váhom
Nové Mesto nad Váhom

You may have to brush up on your latin and or hungarian languages. Also understand spelling is often arbitary...it seems the records are often 'spelled' by pronunciation.

Good luck.