Don't forget that you should re-register for gifts about 2-4 weeks before your bridal shower. Now if your shower is a surprise then make it 3-4 months before the wedding date.
The reason you want to re-register, and you'll want to re-register about a month before the wedding too, is to ensure that your guests will have items to choose from. Your originally registry may have been purchased as engagement gifts and some items may no longer be available. Remember that seasonal items (holiday, summer) are only available for a limited time.