can any one tell me how to figure out if my car is a 2006 or a 2006.5(made after august)

looking to order spacers but the size of the lugs changed between the half year.

 

On the rear of the driver's door column near the lock you will find the year and month of production on a sticker. You could always look up your VIN number and that will tell you if the door sill has been repainted

 

Since you have a very specfic reason for a single piece of info, simply measure your lugs/studs...take one off, and simply check to see if a " standard" size lug bolt/nut will fit on it from an auto parts store...
Often mini reports a date for a change over, but a few cars, either due to the car getting extra work at the factory or other issues will sometmes meet the earlier/later standard...so if your date is anywhere close, do a physical check!