A list of hidden sheets will be displayed - select "Weapons" and hit OK
There will now be a Weapons tab on your workbook, go to it.
I'm not 100% sure how the dropdown lists are set up, so I'm not sure how to make it select from a longer list of weapons.. so easiest thing to do is probably replace a few of the swords in there with the fist weapons you're interested in.
It should be straightforward enough apart from the Proc DPS for fist weapons with procs.
One thing i found when i was tweaking it to support my CotBD was that adding it as a Fist weapon in the swords section of the weapons sheet broke things (no idea why - my excel-fu is exceedingly weak [and i was using open office anyway, if that matters at all]). In the end, i just added it as a sword, selected 0/5 sword spec, then added the bonus 5% crit in the gap between the racial stats and the gear stats.
There's also the issue of whether the fist spec crit increase applies to the MH only, or both MH and offhand, when you're using a non-fist offhand (i'm using a CHT, for example). Last i heard that was an unresolved issue (i've seen multiple parses - some that could be interpreted one way, some that seem to indicate the opposite).