khimm19:
so how can i control the servo motor and the HC-SR04 if i will not draw any current from other devices from arduino?
Powering the HC-SR04 from the Arduino 5v pin is probably OK, but not the servo.
If (as @Wawa has suggested) you use a 5v regulator to power the Arduino then you could also use that to power the Servo and the HCSR04. If it is a small servo the 500mA should be sufficient.
...R