I counted 33 stars in your coin going around about 2/3's of the way which means a star every 7 degrees approx. Hit Ctrl+R to show rulers,if the Smart Guides are not on hit Ctrl+U to turn on, now drag a guide line from the rulers that run down the side out to the centre of your coin that will give you a vertical guide, now from the top drag a horizontal guide down to the centre of your coin. The smart guides will give you a light cyan line running off at a angle once you reach the centre point. Now if you open your rotation dialogue box with your star selected and enter 7 if you want to C/wise or -7 if you want to ACW hold down Alt key and drag the reference point to the guides centre and the hit copy in the dialogue box. If you have CS5 or later I think you can type how many copies that you want but I have only CS3 so I have to keep using Ctrl+D to Transform again and again to rotate the star around the centre of the coin. I hope this helps and please remember to press F1 to bring up the Help programme and then enter "rotation" in the search option which give great help.