Partition table entries are not required to be in disk order. They work fine if they aren't. Why do you want to "fix" this?
Regardless that you don't need to do this, just be sure to backup your partition table before diddling with it ... that way you can recover if you screw it up.
A simple backup is this (change "/dev/sda" to your actual drive designation):
dd if=/dev/sda of=mbr.bin bs=512 count=1
WARNING: DO NOT MIX UP THOSE "if" AND "of" SPECIFICATIONS!!! You will trash your MBR if you mix them up.
That will backup your MBR (which includes the partition table). Make sure you copy that "mbr.bin" file somewhere else besides on the hard disk that you are diddling with! And make sure you have a LiveCD to restore it with, should that be necessary.