The pilot reported that, while on a visual approach at 700 feet, the airplane experienced a total loss of engine power. The pilot immediately recognized that the selected fuel tank was empty because she had forgotten to switch fuel tanks during the flight. She attempted to restore engine power by selecting the other fuel tank, which did have fuel remaining, and activating the auxiliary fuel pump. Partial engine power was restored, and the pilot decided to land at a nearby private airstrip. During the approach, the airplane's right wing struck a tree, resulting in substantial damage. The pilot continued the landing and during the landing roll, the nose wheel contacted soft gravel and the nose gear collapsed, resulting in impact with terrain and substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.