What's the best way to heat a old mobile (1973) with limited power and lousey insulation?

The mobile is powered off a house up the hill and has two electric heaters that run almost 24/7, one is rated at 1100watts and the other is set to 700watts. With the computer running and everything else (lights, tv, dvd player, fridge) if i turn the second heater to 1100 watts the circuit breaker pops. Propane heater that came with the place is inefficent and Propane costs 250.00 per 100 gals. Also electricity runs $190.00 a month with said load and varies +/- $10.00 from Nov. to April. Rent is 450.00 a month. Maybe i should just move, but! it's up here in the mountains of southern oregon and just breathtaking views and clean well water and fresh air make me think twice. thanks for any input. Also limited buget, but i would concider options running just less than 1000.00.