Hi,
The upgrade process from 3.0.1 to 4.2 will be.
From 3.0.1 to 3.3.x
from 3.3.x to 4.1.
Once the DB is on 4.1 the ACS version 4.2 will be able to read it.
In order to get this software you need to have a contract that allow you to have all those ACS versions.
My suggestion open a TAC case and we will make the convertion from 3.0.1 to 4.2 for you.
If you have any question feel free to contact me.
Do rate helpful posts.