Replacement of 2N3822 and 2N5640 for a 0-12v adjustable power supply
Jfet's are becoming rare.  You will only need those current source jfets if you want to get to zero volts.  (If you can live with 1.25 V as V min, then...)  

So what you want to do is match the zero gate (Vgs=0) current drain.  Here's a list from digikey.  Your job is to find out the value for the jfets in your circuit.  (I would think that they could be the same jfet??)