There is a basic map to that area of the park, I am sure you can get it online at Amazon, Waterstones or Stamfords. I'd let you have mine, but I gave it to two Dutch girls in El Calafate. 2-3 hour walks each way from Chalten to viewing points for Cerro Torre and Fitzroy groups, traverses between view points of similar time. Walks up to the edge of the glaciers for each from these points 30-90 minutes each way.
Just a quick trip report for anyone else who might be interested in this destination; from El Chalten we simply did a 3 day trek, following the well-marked paths between the different viewpoints. It was all very (too?) easy. We used the free campsites Poincenot (near Laguna de los Tres) and De Agostini (near Laguna Torre) - both have running water nearby and a basic toilet. At the end of October they were quiet, with 4-5 tents in each.
Other tips: buy food at El Calafate, it's much cheaper. Gas cartridges were readily available. The hostel we used in El Chalten was the Glaciar Marconi which has just reopened and is half the price of the other hostels. It's basic but okay.
I hadn't fully appreciated how well-developed the tourist industry is; we were very early in the season and it was already getting busy. Most of the walks could be done in a day from El Chalten, but it was definitely worth camping to get to the viewpoints before rush hour. It was cold and windy but the weather was incredibly stable and we had plenty of sunshine.
While it was great to see Cerro Torre and Fitz Roy, I don't think I'd really recommend the area. With more planning I think a more fulfilling trip could be done in a less visited part of the country.