invalid node structure and invalid sibling links on hard drive help?!!

Hello. I'm having some trouble with my Macbook. It's running on Leopard 10.5.8. I recently tried to partition my hard drive and while doing so it prompted me informing me that there was an 'invalid node structure'. I could then no longer proceed with the partition. I had planned on updating my OS to Snow Leopard. I wanted to partition my internal HD, so I backed up some files on my external HD. I basically wanted my interal HD to run smoothly with a new OS while minimizing the space used. Now I've come across this issue where there is another message being prompted that says, 'invalid sibling links on hard drive'. I found THESE steps on another forum that informed me that this might restore the hard drive back to a readable/functional state but that didn't work either:

(These were the steps I took and nothing happened except another prompt informing me of an 'invalid node structure')

1. Boot off the OS X CD (reboot, hold C while booting).
2. The installer will load up, go to Utilities in the menu and run Terminal.
3. Type df and look for the drive that has your Mac system mounted---you'll have to unmount this. On my MacBook Pro, it was /dev/disk0s2.
4. Type umount /dev/disk0s2, replacing disk0s2 with whatever disk your OS lives on.
5. Type fsck_hfs -r /dev/disk0s2. If you umounted the wrong thing, it will complain that you can't repair a mounted drive. Go back and umount the right thing and repeat this step.

I then stumbled upon a few different forums mentioning something about Disk Warrior. I was wondering if THAT would resolved this issue. Honestly, I don't really want to spend much money on buying this but I WILL buy a new hard drive if I ABSOLUTELY need to. I was just trying to see if I can troubleshoot this before I decide to throw in the towel and buy a new hard drive or attempt to try out this Disk Warrior thing.

Help please!