Just go to the "All" category on the
impulse store and then sort by popularity.
Popularity just correlates to sales within the last 7 days, so far as I can tell. The only games on all of impulse that are presently beating out AI War are Sins of a Solar Empire - Entrenchment, Demigod, and Hero's Tale Enhanced Edition.
On our last sale in June, we never got higher than the #7 mark. I think the difference is a mark of the game's increasing appeal and exposure, and all of the great promotion efforts of existing fans of the game (thank you all who mentioned the game elsewhere!).
Hopefully AI War will stay in the top 10 or so for another weekish, and then hopefully we'll be back to our usual haunt in the top 20. The lowest we have dropped since our first sale was I think 33rd (out of 250+), so we do pretty well in general on Impulse, but there's a huge difference in volume of sales between even being 16th and being 4th.
Pretty cool, anyway.
EDIT: Now, on the 24th, it's up to #2! It's beating out everything except the expansion to Sins.