The pilot stated that he was conducting an instrument-flight-rules flight with an estimated flight time of 1 hour and 33 minutes. He encountered unanticipated headwinds along the route of flight, and as he neared his destination airport he learned that weather conditions had deteriorated below minimums. The pilot diverted to a nearby airport, but was unable to complete the approach due to a windshear encounter. He then diverted to a third airport and reported that he was concerned about the airplane's available fuel. The pilot again aborted his first approach due to a windshear encounter and during a subsequent approach the airplane experienced a total loss of engine power due to fuel exhaustion. The pilot performed a forced landing to a field prior to the runway. The airplane's nose and left main landing gears collapsed upon contact with a ditch, which resulted in substantial damage to the left wing.