I have an adapter which I bought which is easily has all the switches for 1.5v to 15v in increments of 1.5 volts. Measuring it alone is has almost accurate voltage levels. It supplies 300mA max.
Now I am kinda cheating it and using it as power supply. How can I bump the current or decrease the current level by adding another circuit after the power supply.
It is possible to use a LM317 in the current mode. Look at fig 7 on this link and make R1 a variable resistor in your case. This circuit you will then hook up in series of you power supply.