Upgrading an Asus hard drive

Hello!

I recently tried upgrading the hard drive in my laptop (320GB to 500GB), but Windows still recognizes it as a 320GB drive. I used HD Clone 3.8 to clone my hard drive. I checked Disk Management and it showed the extra space as being unallocated. I tried using Partition Manager to resize my partitions (my laptop came with two: C: Vista and D: Data), but it would only allow me to fiddle with a Local Partition (which seems like a hidden recovery partition that I wasn't aware that I had) and the C: partition.

Since I have little experience partitioning hard drives, I left that alone. It wouldn't allow me to resize the D: partition using the unallocated free space, either. I could create a new partition using the unallocated space, but I have my Steam directory on the D: partition, and I don't want to deal with managing 3 partitions.

I guess my question is, is there a way to resize my current partitions, or do I have to do the whole cloning process again using a different method?