How much current does this stepper motor need?
A datasheet would help, but what you have there sounds good enough to design the drive circuitry.  Yes, it looks like each winding has 1&Omega; DC resistance, and that in steady state can handle 2.3A, which means 2.3V.  A drive that never exceeds 2.3A into any coil will be safe.

Because the stepper motor windings look heavily inductive to the driving circuit, it is allowable to apply more than the steady state voltage when switching.  The real spec is the current because the limiting factor is heating of the winding, and that is the current squared times the winding DC resistance.

The simplest safest approach is probably a fixed voltage drive.  That means the current will ramp up as a voltage step is applied, approaching the steady state value of 2.3A with a exponential decay.  If you want to get more fancy and need the fastest possible stepping speed, then current control is better.  The circuit will attempt to regulate the current to 2.3A, which will automatically start at the maximum voltage, then decay down towards 2.3V in steady state.