I don't think there is any way to get a continuous 30mA from the supply you have; it doesn't supply enough power to have 30mA at reasonable voltage. You could have your circuit run intermitantly - Charge a Cap for a while then run the circuit until the Cap is discharged then repeat.
If the load does not need the voltage of the source, i.e. a single LED where most of the voltage is burned off in a resistor- there are dc/dc conversion methods, but it's relatively complicated.
As already mentioned, you don't give anywhere near enough information for what you are trying to do - as your question is phrased it's totally impossible - you can't create something from nothing.
Try posting EXACTLY what you are trying to do, and EXACTLY what you already have, and we can then (possibly?) offer suggestions.
there shoudnt be a problem with that actually. if you take an NJFET and short circuit it's gate and source - and connect em to the input voltage of you're circuit and the njfet's Drain to some higher voltage, it'll act as a current soure. thats how i connect LEDs to a not regulated voltage line.
ok just to re-inforce nigels comment abt not enough into
You state your cct needs 30mA, then you ask to boost your present to 25mA.This contradicts with your 30mA statement.
As your present question is worded IF we were able to help you boost teh current to 25mA (as you asked) the 1st statement abt the cct needing 30mA would mean the cct would not work and teh voltage rail would collapse.
More info
Also
You state you have 17.5V and 1.5mA being drawn. For staters 17.5V is an odd voltage - why are you using that voltage.
I take it that the 1.5mA is what your cct is drawing at teh moment NOT the limit of what your powersupply can deliver. Your circuit WILL only draw as much power/current at it requires to operate. If your cct at present ONLY required 1.5mA then that is all it will draw.