I don't quite understand why you'd want to fix your x-axis, but never mind: That timeline from Oct_this_year to Sep_next_year:
You'd need a mapping table to do that where you use
- a field generated with the MONTHNAME() function (that'll return you sth like 'Oct-2013')
- a (handwritten) field "month_1", "month_2" etc.
=> You could then use the field generated through the ApplyMap() function as dimension to your chart.