The question is:
Can you read
German? Latin would do, too: Förstemann gives many Latin translations of the Germanic name elements. But the most interesting part is the lists of names he gives, including century and source. Together with the supplement mentioned, Förstemann still is the standard work on old
German names.
Another book is:
Wilfried Seibicke: Historisches Deutsches Vornamenbuch I-IV, 2000 ff. (This includes foreign names as well as long as they appear in Germany)
A book to buy (if you know
German) would be:
Rosa und
Volker Kohlheim, Das große Vornamenlexikon, Mannheim 2003
The rest you may be able to get hold of in a good library
Andy ;—)