Rhoda, I would add a DNA tag to this question to get the best answers from those that know.
All I can tell you is if it is your paternal line, the most important test would be the YDNA test of the highest level that you can afford. The "Big Y" will give you the best results, but also the most expensive.
Autosomal will give you results from all connections and the most results.
MtDNA will give you results from your materanl side.