If your controller doesn't have the option to expand the volume, you will need to either
a) recreate the array (you will lose all data on the drive)
or
b) backup the current array (image the array), recreate the array on the new drive using all 500gig, then restore the image. NOTE: depending on the backup software, some will restore an image to the original partition size. There should be an option to adjust the partition size.