Your computer is limited to 128GB formatted capacity, no matter how you partition the drive.
You have three options to remedy this:
1) Purchase an internal PCI ATA controller card -- most all of them support drives larger than 128GB (Sonnet's Tempo ATA/133 cards do for sure)
2) Put the drive in an external USB2/FireWire enclosure. Most all external enclosures support drives larger than 128GB and also support booting from the external enclosure
3) Use modified software drivers that allow your computer to "see" more than 128GB of any drive. I can't remember the exact link or name of the company that provides these drivers, but I'm sure someone else does... fryke! bobw! Where are you when I need you?!