I presume you are considering installing a satellite dish inside a residence (like in an apartment in a building that prohibits satellite dish installs)? Also, since you specified the Wally (which is a portable receiver), are you also talking about using a portable antenna like a Tailgater or Playmaker with it, or just a standard Dish 1000 dish? A little more info regarding the situation is needed.
It is possible to use a standard satellite dish from inside a residence - I've seen it done before. However, you have to have a window pointing in the correct direction supplying a clear view to the satellite(s) at the correct elevation. If the window has a screen, you may have to remove it. Also, if the window is double-paned (especially those with energy efficient features, like gas between the panes or a reflective coating on the outside) it significantly decreases the likelihood it will work.
In short, you won't know until you try.