OK, do what Stewart says, too.Re: range.
Practice scales as quitely as you can whithout adding arm tension as you ascend the scale. When you can play high quietly, you can play loudly, too. Vice versa, not so much. Do them at the beginning of your session after your warmup. Trying to do them at the end leads to bad habits. Get a better teacher, too.
Also, for all the shyte you post on here and the garbage horns you buy, I'd have thought you could play at least an unreliable G an octave above the staff. Spend less time playing on the vandamme computer and more time playing with an actual lesson plan.