The MEMS sensors drift.
The gyro on its own is therefor not enough.
If you use an extra accelerometer, you can stabelize the gyro + accel combination. But you still don't know the direction. So you also need a magnetometer.
If you also want to know the height, you need a barometer. The gyro + accel + compass + barometer is called 10DOF.
You probably want something like the teapot demo:
For that, you need an accel + gyro. The MPU-6050 is a good sensor for that and are only 5 or 6 dollars on Ebay.
Use the software created by Jeff Rowberg, http://www.i2cdevlib.com/