Line Graph with Month Name + Year in X Axis

Hi, I am making a line graph that shows how many tasks are created for each month. The month basis will be from tb.taskcreateddate.

I tried to make it specified order and change to each month, but the problem is, it doesn't show the month as month name but month number and year.

Image may be NSFW.
Clik here to view.

I need to show each month like Aug 2013, Sep 2013 till Jul 2014