How do i add extra dimensions to a screenshot?

I currently have the code below.. and it takes the screenshot just fine.. but it cuts off the left and right side of the screenshot

It also doesn't seem to always take the middle of the focus app as well.

How do i add another 50 pixels all around possible?

print "Taking SS..."
focusWindow = App.focusedWindow()
regionINFO = capture(App.focusedWindow())
shutil.move(regionINFO, os.path.join(r'C:\Screenshots', 'Dummy1.png'))
print "SS Done..."