Although I'm certain most have these, I thought I'd list out some of the modern materials I have regarding this time period. n Hope the post isn't too long.

Pre German
Archeology and language (Renfrew)
A great book written by someone not afraid to rethink the facts. Even though many do not accept his analysis of the origins of PIE, recent work in the Black Sea may eventually bear him out.

In Search of the Indo-Europeans (Mallory)
Very readable. Helps one to sort out what is PIE from later innovations.

Early German
The Germanic People: Their Origin Expansion and Culture (Owen)
Solid work about the early Germans

The Germanic Invasions (Musset)
Good fun when I'm rethinking history. Lots here.

A Hitory of the Ostrogoths (Burns)
Haven't had a chance to really look at this, but it has a lot of material about this period.

The Barbarians by Tim Newark
Light but very interesting. I would recommend this to anyone who wants a visual picture and a quick glance at the period.

The World of the Huns (Maenchen-Helfen)
Excellent, with good insight into that which drove the Goths West.

Later
Beowulf (original and a translation by Charles Kennedy. (When I was in college I ran across a translation by Tolkien which I believe to be superior)

A Middle High German version of Der Nibelunge Not (with a grammer and short Dictionary) By Prof Dr. W. Golther (1904 print date)
I love this book, even though I can only read parts.

West Viking: the ancient Norse in Greenland, and North America, (Mowat)
Good Source for the western most expansion

A History of thh Vikings (Jones)

Gods and Myths of the Viking Age (Davidson)