I'm reading "The last Offensive" by charles B. MacDonald at the moment, downloaded here from the main site, and found the attached map in the book which shows the units arraund Siegburg in early April 45. I have marked Siegburg on the map.
Also from this book, page 366:
"In the course of the advance almost every division overran a number of military hospitals, and several units liberated prisoner-of-war camps. At Waldbroel, not far north of the Sieg River, the 78th Division freed 71 hospitalized American soldiers, only 2 of whom were able to walk. At Hemer the 7th Armored Division rescued 23,302 prisoners of war, most of them Russians, living under appalling conditions of filth, disease, and hunger. The only Americans, a group of 99, were in fair condition, having been assigned to the camp only a few days."
...but no word about Siegburg 
Christoph