OPAMP Help needed

I am using a sharp GP2d12 IR sensor with a 4.8 V battery and trying to power a vibration motor. The motor requires a 80 mA current to start and has an operationg range of 2 -3.6 V. Unfortunately the sensor only supplies 5mA and ranges in voltage from .5-2.6 V. What OPAMP or other device can I use to get this motor to vibrate harder, the closer the object is to the sensor?

Rotary vibration motors have an eccentric weight attached to the shaft. The only parameter you can change is the frequency of vibration, not the intensity. Is that what you want?

Sure you can change the intensity of a vibrator.
Vibrators have a variable resistance in series which can increase the power to the motor enough to vibrate her socks off!
Then the frequency (the RPM of the motor) also increases.