Yeah, definitely pick up an oven thermometer! We've got an enormous beast of a catering oven on our boat (ex-hotel barge) and the dial is so off that we're not certain whether it's in F or C, but with the oven thermometer, we're able to know about where on the dial to set it to get the temp we need.
Another good thing is to get a pizza stone, or put some bricks in the bottom of the oven. Both really help to distribute the heat more evenly, but you've got to give either ideally ~30 minutes to warm up before they do much.