There are two important specification for your charge controller that are important in this situation: maximum input voltage and maximum output current
your existing 140 watt, 19 V panels in series and then paralleling them with a new 240 Watt, 48 V panel should work, but it will be very marginal.
The rated input voltage on your controller is 57 V but the recommended maximum is 45.6 V (who knows what that means!!!). When your batteries are full and your controller starts raising the input voltage to keep the current low, the maximum input voltage will go to 48 V, somewhere between maximum and recommended. You figure out what the risk is here?
The maximum output current for that controller is 40 amps at 12 V or 480 watts. In full sun you will be making 520 watts at the panels which will be maybe 10% less at the output due to bringing all three panels to the same input voltage as well as controller conversion losses. So it wll be real close to 40 amps in direct, perpendicular sun. Most controller manufacturers and design codes suggest reducing the current rating of controllers by 20% or so as a safety
factor, so you could be in trouble there.
Like I said it will be marginal, but may work. I would be happier with a new 200 watt, 38 V panel.