I've got a problem with a USB drive I used on windows before I swtiched to my MBP.

It was a 500mb volume (1 partition of NTFS). It contains all my music, video etc. from when I used the windows machine, and I don't want to lose it. Before I got my MBP I shrunk down the volume to about half the disk and left the rest of it unallocated.

When I plug it in to the MBP, it mounts the NTFS volume. Going in to disk utility, I can see the NTSF volume and the unallocated space, but I can't do anything with them (i.e. format to HFS+) without seemingly erasing the disc. Is there a way around this? I ideally want to split the disk between the NTFS volume and HFS+ without losing the existing NTFS volume.

Any ideas?