Impulse Anywhere is what you're looking for I think.

While that's true, the OP's problem is just that he doesn't have internet at home and has to use a library computer.

In that case, Impulse Anywhere is currently the only option available as folks have mentioned. It's a web-based download that doesn't need the Impulse client. These archives can be installed completely offline. In the future, once they stop putting out 2-3 updates/month, they will DVDs with the latest up to date version that you will be able to get mailed to you. For now, you're going to have to use Anywhere.

The reasoning is nothing particularly sinister, just that Impulse updates by a direct file comparison between your local installation and the version on the distribution network, and then directly replaces any file that needs updating. The benefit is that they don't need to continuously test standalone installers and can increase the frequency of updates. The downside is.. no standalone installers are possible

You couldn't really go wrong with uninstalling the unpatched game first and then installing fresh, but if the installer doesn't complain that it's already installed, you should be good also.

Well, that presents another problem: I currently don't have anything large enough to download 2 gigs worth of data. Oh well. . . guess its off to find a larger thumb drive (or hauling my rig to the campus library. . .). 

A good question to ask before I pursue either of the above options would be: Can the downloads from impulse anywhere be accidentally recognized as torrents by an extremely secure/picky network? Only reason I ask is because I know of direct-to-drive downloads being blocked by the campus network before even though they are from 'good' websites (I use quotes because you still shell out 50 dollars for a game you never get to play).