[Hocrest]

That is the cam sensor, and yes you do need that to run the car. There should be 2 bolts with a 10mm head, about 25-30 cm(?) long to hold it into place.

If you stand by the drivers side front wheel and look at the front of the head towards where the back of the cam wheel (what the timing belt wrapped around) you should see the round hole that the sensor pokes through. The wiring is just about the right length, you can use that to determine about what area the sensor goes to.