jonwhite:
my advice is find what chip it is and make up the circuit you will learn so much from doing it.
No making a stable switching regulator is difficult. The PCB layout is critical, I have never known even an experienced professional, PSU specialist, engineer get it right first or second time.
You have to know what you are doing. If not you are just wasting your time and money, and unless you have proper test equipment you can never succeed.