So there isn't an update that can actually be downloaded and installed seperately from the main game at all? I actually have to download the entire game in order to get a single measly little update?
As has been noted, Impulse autopatches the game when a new patch comes out. In this case, the relevant files that are altered, usually the executables and a number of .entity files, are downloaded in an archive, which is then unpacked into the appropriate directories, replacing said outdated files with the new ones.
It's an entirely automated process, so long as you run Impulse and have registered the game with Stardock.
IIRC, going from v1.00 to v1.191 was a few hundred megabytes. OTOH, going from the version in Trinity (v1.181/1.041 base Sins/Entrenchment, IIRC) to the current v1.191/v1.051 would be a couple of megabytes at most. Patch changes between 1.041 and 1.051 aren't particularly massive overhauls, just minor balance fixes and engine tweaks.
So you should be able to update it through Impulse relatively easily, despite having Dialup/poor broadband connections.
But to answer your question, separate patch executables have been discontinued since the full integration of Sins into Impulse, which occurred post v1.05 Base Sins. So v1.05 Base Sins is the most up-to-date separate patch installer available for Sins.
Obviously useless to you.