Camera circuit with different voltage requirements on arduino
A voltage divider is not a good idea because the output voltage will depend too much on current draw, or it will always draw lots of current from the supply.  A better idea is to linearly regulate the 3.3 V supply down to the other voltages you need.  That will be somewhat wasteful of power, but if the arduino supply can handle it, it will be the easiest solution.

Whenever you say you need to power something at a particular voltage, you should also mention the current requirement.  Since you didn't, there is little more specific advice to give.  If it's only a few 10s of mA, then linear regulators are a no brainer.  If it's 1 A then it gets more complicated, and quite possibly the existing power supply doesn't have enough extra to provide that power.