In that case you can of course still use the bot to find all the places you might want to change, and decide manually. But I'm not sure if I want to do this.
I don't see any way to decide just with regular expressions on if to replace or not, and even if I would use someting Turing-complete, I wouldn't know on how to decide if this $2 is transformed to coins or not.
:e But actually, I don't really see why this "$13 or $16" shouldn't be in coin images (except that maybe we don't have good images with double-digit numbers). The currency in Dominion has always been "{{Coin}}", and "$" only occurs because "{{Coin}}" is not in UTF-8 (I think), and at least not in ASCII. But I don't think you would find a single "$" in the rulebooks, and if there would be some tactical advices in the rulebook like "... it is easy to get to $13 to $16", I'm sure it would use "{{Coin13}" and "{{Coin16}}"" instead of "$13" and "$16".