How far could / should I be able to hit my driver?

The problem is (and I'm sure your pro will agree) that if you are slicing your woods, causing a loss of distance, you will also be pulling your iron shots giving you an increase in distance (especially the short irons).
This means that when you fix the slice, the low end of the iron distances posted above will be approx your max distances, however that should work out at hitting a driver approx 255-260 carry which is very good indeed, just rubbish by forum standards!