Based on the picture and the dimensions it sounds like an insert is the simpler option. I generally prefer a free standing stove, but inserts are very good heaters. I easily heat 1,700 sf with an insert. There are a lot of options that will work with that fireplace. 
Something else worth mentioning: the newer EPA regulated wood stoves/inserts require well seasoned wood. They burn differently than the dragon in the basement.
	
		
			
		
		
	
				
			Something else worth mentioning: the newer EPA regulated wood stoves/inserts require well seasoned wood. They burn differently than the dragon in the basement.
 
	 
	 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		

 
 
		 
 
		 
 
		 
 
		 
 
		