Hello,
The PNP transistor current limit is quite easy to do. You take a PNP transistor, connect the output of the circuit to the emitter, take the new output from the base, connect a low value resistor between base and emitter (say 0.6 ohm for 1 amp current limit) and connect the collector to the feedback Vc. In addition it helps to add a 100 ohm resistor in series with the base (directly in series before the low value resistor) to help prevent a surge in base current from destroying the transistor.
The idea is that when the current becomes high the 0.6 ohm resistor drops about 0.6 volts and this turns the transistor on slightly and that puts more voltage at Vc so it fools the chip into thinking that the voltage is now too high so the chip starts to cut back. The transistor is much faster than the chip internals so it is pretty stable.
The drawback is the 0.6v drop unless you can stand a much higher current limit.
In some cases you need to also add a series diode in series with the base and the new output in order to produce a larger voltage drop. This is sometimes needed to allow the transistor to properly drive the Vc pin even with a very low output resistance. It partly depends on the nominal level of Vc. If it is 1.25 volts you probably dont need this, but if it is 2.5v you may need it. In any case, you need to carefully check the current limit feature after installation to make sure it will truely current limit down to whatever load resistance you think might appear on the output during normal operation. If it doesnt work quite right then you may need to add the diode.
Another possibility is to install the transistor on the input and still drive the Vc pin the same way, but again check to make sure it works as intended.