I've not found much on the 191st.
Try contacting the men at this page
191st Tank Battalion Reunion Colorado Springs, Colorado; September 6-9, 2006 Photo Gallery by Randy Waltz at pbase.com
Credited with these campaigns:
Algeria-Morroco
Anzio
Central Eruope
Naples-Foggia
Rhineland
Rome-Arno
Southern France.
These boys got around.
Company C formed from Va. National Guard, 29th Tank Battalion (Light)
They were attached to the 36th Infantry Division (ID) in Aug 44 and the 45th ID Aug 44 to Feb 45 and Mar 45 to the end of the war. Look for the division's histories and you can probably find info on the 191st.
edit---found these other attachments 42nd ID Mid Feb - Mar 45, 70th, last 3 days Dec 44, 79th 1 Dec 44 - 22 Dec 44
I do not have info on them for 1942 and 43, as far as what divisions they were attached to, but I suspect it was these same ones, as they tended to keep the tank battalions and divisions together, even if they were supposedly "independent" battalions. They could have been attached to the 1st Infantry Division (ID), 9thID, & 34th ID, as the 36th and 45th were not in North Africa and they got credit for action there.