Here's the converted sheet:http://home.metrocast.net/~adkohler/game/sc2NPCworksheet.xls
I'll probably take it down soon, so those who want it should grab it.
To use it, pick roman numerals for each quality and enter a threat level next to "TL".
As you can see, it's pretty much just a table lookup utility. It doesn't add up costs or tabulate combat modifiers, though those are fairly easy things to do compared to the table lookup part.
The roman numeral cells have drop down selectors. Those that must have values can contain only I-X. Those that you don't have to have a value in (like skills) can be blank as well.
Damage save and VP/WP can both be blank. Obviously, leave the appropriate one blank for the appropriate type of NPC.
As for the lookup tables themselves: I don't think I checked them against the errata, but when I was entering them, there were some obvious errors that I fixed when transcribing them.