Oven doesn't get get hot enough

My original problem started sometime ago. Just recently, I turned the oven on and it barely got warm. After waiting an hour, I started smelling gas, and the temperature inside over luke-warm. I replaced the ignitor today. The over get a little hotter, but not to the temperature for baking at 350. What could be the problem now? Would it be the ole thermo?

It take a least five minutes or so. Model # 32-1272-10 Tappan