Resizing a window in a dual screen display

I am running a gaze contingent eyetracking script that utilizes psychtoolbox on a dual display computer. However, each window that opens fills up screen 0 and spills almost halfway onto screen one. I am wondering how to resize the windows that open. Here is some relevant code.

   %**************************************************************************
      %
      % Present the stimuli and collect eye tracking data
      %
      %**************************************************************************

      %
      % INSTRUCTIONS
      %

      textSize = 15;
      %Screen('FillRect',wPtr,black);
      Screen('TextSize', wPtr , textSize);
      Screen('DrawText', wPtr, 'Press any key to begin', winWidth/2-100, winHeight/2, white);
      vbl = Screen(wPtr, 'Flip');

      while 1 %Wait until a key is pressed
          pause (0.1);
          [keyIsDown, secs, keyCode] = KbCheck;
          if keyIsDown
              break;% Begin with the experiment
          end
      end

As well as this section

        %Data collection parameters
          dataCollectionDuration = 0.05; %Collect data for 50ms
          pauseTimeInSeconds = 0.01;

          %Gaze contingency parameters
          hitStart = 0; %Time the gaze has hit the AOI
          waitForFixation_sec = 2;%Time in seconds the gaze has to hit continously the AOI

          DX = winWidth / 2; 
          DY = winHeight / 2;

          %Define AOI coordinates according to the size of AOI in degrees
          %Distance to screen
          distance_mm = 650; %Approximate distance of the participant to the screen
          AOIsize_degree = 2; %4 degrees in total
          AOIsize_mm = distance_mm*tand(AOIsize_degree);
          winWidth_mm = 510;
          AOIsize_px = round(AOIsize_mm*winWidth/winWidth_mm);
          AOICoor = [ DX - AOIsize_px DY-AOIsize_px  DX+AOIsize_px DY+AOIsize_px];

          %Show the fixation cross
      %     textSize = 24;
      %     Screen('FillRect',wPtr,black);
      %     Screen('TextSize', wPtr , textSize);
      %     Screen('DrawText', wPtr, 'Look Here', winWidth/2-12, winHeight/2-12, white);
      %     vbl = Screen(wPtr, 'Flip');

       %Screen('FillRect',wPtr,white);
          texture=Screen('MakeTexture', wPtr, stimulus1); %Load image 1
          Screen('DrawTexture', wPtr, texture);

          while 1
             lastSample = length(timeStampAll);
             %Collect data for 50 ms
             [leftEyeAll, rightEyeAll, timeStampAll, remoteToLocalTimeAll,trigSignalAll]=DataCollect(dataCollectionDuration, pauseTimeInSeconds, leftEyeAll,rightEyeAll, timeStampAll, remoteToLocalTimeAll ,trigSignalAll);

             %state = 1 --> all the ET samples hit the AOI ; state = 0 --> none or some of the ET samples didn't hit the AOI
             if lastSample < length(timeStampAll) %if new samples have been collected
                 validityLeft = leftEyeAll(lastSample+1:end,13);
                 validityRight = rightEyeAll(lastSample+1:end,13);
                 GazePointLeftX = leftEyeAll(lastSample+1:end,7)*2*DX;
                 GazePointRightX = rightEyeAll(lastSample+1:end,7)*2*DX;
                 GazePointLeftY = leftEyeAll(lastSample+1:end,8)*2*DY;
                 GazePointRightY = rightEyeAll(lastSample+1:end,8)*2*DY;

                  state = HitAOI (AOICoor, validityLeft, validityRight, GazePointLeftX, GazePointRightX,GazePointLeftY, GazePointRightY);
                  if state %if the gaze was inside the AOI:
                      if hitStart == 0 %if it wasn't before, start counting
                        hitStart = tic;
                      elseif toc(hitStart) >= waitForFixation_sec %if it was for at least the time predefined, exit the loop and present stimulus
                        break; 
                      end
                  else
                        hitStart = 0; %Restart count
                  end

                  %Redraw to update the frame status
      %             textSize = 24;       
      %             Screen('FillRect',wPtr,black);
      %             Screen('TextSize', wPtr , textSize);        
      %             Screen('DrawText', wPtr, '+', winWidth/2-12, winHeight/2-12, white);
       Screen('FillRect',wPtr,white);
          texture=Screen('MakeTexture', wPtr, stimulus2); %Load image 1
          Screen('DrawTexture', wPtr, texture);
                  if hitStart > 0
                      Screen('FrameRect',wPtr,[0 255 0], AOICoor);
                  end
                  vbl = Screen(wPtr, 'Flip'); %Flip
             end     

          end

          %
          % STIMULUS 1 - IMAGE 1  
          %

          timeStimulus1sec = 3; %Time the stimulus 1 will be shown
          frames1 = round(timeStimulus1sec / ifi);

          %"BACK" SCREEN - Prepare stimulus 1
          Screen('FillRect',wPtr,white);
          texture=Screen('MakeTexture', wPtr, stimulus1); %Load image 1
          Screen('DrawTexture', wPtr, texture);

          %FLIP BACK <--> FRONT screen
          vbl =Screen(wPtr, 'Flip');
          stimulusOnset(1) = vbl;

          %Collect data - Less than the total time - we don't want to miss the next "flip"
          [leftEyeAll, rightEyeAll, timeStampAll, 
remoteToLocalTimeAll,trigSignalAll]=DataCollect(timeStimulus1sec-0.3, pauseTimeInSeconds, leftEyeAll,rightEyeAll, timeStampAll, remoteToLocalTimeAll ,trigSignalAll);

Thank you