Trying to trace my grandfather's military career

[Immelmann67]

I'm trying to trace my grandfather's military career in WW2. I have established a few things so far, mainly with the help of recollections of my mother and information gained from WASt, but their records are incomplete.
The information I have so far is all collected at [url]http://mainly28s.com/zBrings/Granddad.html[/url]. Could anyone possibly expand on this (based on the units listed, the info given and the photos), and recommend some more books or sites to read? I'd also love some clarifications of what the info actually means.

The bare bones are:
His Wehrnummer was: Neuß Grevenbroich 10/103/9
From 1939 to 1941 he served in:
1. Batterie leichte Artillerie Abteilung 745 (Feldpostnr 27425B)
Unterstellung: 1. Gebirgs-Division
Einsatzraum: 1939 Südpolen, Lemberg
Oktober/Dezember 1939 an der Eiffel

Dienststelle (Truppenteil usw, Standort): 12(E)/AR6 Lingen (Ems)
Truppen-(Kriegs-)Stammrollen-Nr Ranglisten-Nr was 269/39

After 3.4.1941 he served in:
7. Batterie Gebirgs-Artillerie-Regiment 79 (Feldpostnr 30062B)

Apparently he was promoted to Feldwebel towards the end.

Any information would be appreciated.

Thank you in advance

Olaf Meys