No you will not have to buy a new gear stick but you have to make sure that you either cut the Gear Gaiter (this is the part that covers the ugly stick) very neat or else you might as well buy a new Gear Gaiter.
To remove the Gear Knob simply untie the Gear Gaiter from the center console with a Torx Screw. After which pull the Gear Knob towards you (this may need some good pulling!) and it will eventually come off with the whole Gear Gaiter. (The gear knob of the saxo is bonded with the Gaiter)
After which simply cut the Gear Knob off with a Saw (till the point that the other gear knob will fit) or else install the new Gear Knob with a new Gear Gaiter (i prefer a new one!)
It is also possible to fit a new handbrake cover as told previously.