Can the servo pulse width range be changed?
The Servo Attach method has two forms,

servo.attach(pin) 
servo.attach(pin, min, max)


In the latter form, you can specify values for the min and max microseconds that servo.write() will use to represent 0° and 180° respectively.  

Note, default values are 544 μs and 2400 μs, which is not so different than the range you say you want, so perhaps some other problem is afflicting your setup.

Also, as explained in my answer to question  “Change Servo Speed With RedBearLabs BLE Shield”, you can issue servo.write(value) calls with value in microseconds instead of in degrees, which may allow more precise control.