You can pick up a Sony DRU-500A. Its the first drive to burn both + and - disks. They run about $350 for an internal unit. You can pick them up on ebay for about $300. But if you want to skip the fighting on ebay, check CompUSA, C.City, BestBuys, Staples, ect ect. Or you can even be real lazy and buy it right from Sony, for $350. This way with a drive that burns both + and - disks you can pick rights right for what your trying to do. I'm getting my self one of these and use the burner I have now as a back up.
*All prices in UDS
You can read about this drive on Sony's website:
SonyStyle - DRU500A