i put the disk in and following the prompts via steam and now installing?
I don't understand what exactly you mean. Do you mean Steam is updating the game by downloading the patch? You would have been better of by activating by Uniloc & just downloading and installing the patch yourself.
Sounds like Steam is downloading the patch since, if you had inserted the disc, that means you've installed the game from it, but chose to activate it through Steam. Once activated, Steam by default is enabled to auto-update your games and so it sounds like that's what it's doing. The slow speed is a result of a slow internet connection most likely.
Run a test on speedtest.net and report your results to confirm.
I had this problem. For some strange reason I put the disc in and then it decided to download the whole game from Steam. I stopped the download, reloaded my disc and then it installed it without Steam. The only time I had to use the internet was to download the patch.