If your goal is to tip the teeth outwards, it shouldn't take that long, but every case is different. As for expanding the arch- that, more then likely will. The typical process is to expand, then bring the teeth together, then fix the arch and then tip the teeth. Either way, getting your ortho done won't be in vain. You'll have to fix your teeth and then go to more invasive procedures.
I would look for a second opinion though. A lot of orthodontists these days still use old age methods- find someone that has a "modern" approach.
