Those bills look pretty normal to me, comparable to our 1200 sqft house. Think of it on the level of energy, heat is energy. warming the air for your comfort is pretty inefficient, cook more meals at home and eat hot foods as suggested by fat charlie.
By not owning the place it kinda limits your choices on improving it. But I would also take a look at improving the efficiency of the boiler unit. insulated boiler lines, insulating the floor helps too.
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