The accident airplane crashed on airport property after reporting the airport in sight during a night IFR approach. The pilot reported the weather at the time of departure was 500 feet overcast with visibility restricted to 1.5 miles in freezing drizzle. The pilot reported he was unable to reach his assigned altitude of 9,000 feet because of structural icing. He also reported an uncommanded decrease in RPM in the left engine during the en route climb. He reported to ATC he could not maintain altitude and requested an 'immediate' return to his departure airport. The pilot reported the airplane stalled as he was turning from left base to final for the landing runway. He recovered from the stall and decided to 'place' the aircraft in a field. The pilot reported another stall, 'a few feet above the ground and crashed.' A post accident inspection revealed ice buildups on the leading edge of all airfoil surfaces and the underside of the wings. No mechanical defects were discovered in the left engine or propeller system.