is there any way i could reduce the voltage reliably with a simple circuit.
3..5 diodes of a proper rating in series with the supply would be simple. The exact number depends on the voltage drop of each under the load present.
i was looking at using an lm317
What's the max. current?
LM317 is good for 0.5A, 1.0A or 1.5A depending on their suffix (like LM317T which is 1.5A or eg. LM317H which is 0.5A).
LM338 (the bigger brother of LM317) OTOH is good for 5A (7A peak) and it calculates the same way.
but i'm a bit confused about how to find the resistor values. for r1 i was going to use a 2k and a 22k resistor. will i need an outrageous input voltage or will 19v work?
That's too low an impedance for proper regulation. You need to allow at the very least 100µA to allow that (and that's the bare minimum). It's better to allow at least 1mA of adjust current (like R1=1k and R2=11k).
Don't feed it 19V! I have yet to see a laptop that doesn't got hot and there's no reason to strain it further, as the electrolytic caps will only die sooner.
Personally, I'd use a string of diodes.