The program package is 31.5mb and the User Manual, which is a separate download is 580.5kb.
If your download is stopping at 1.7mb, then you are having a download issue. Don't worry though, because when you do download it successfully, it will either be "resumed", or will "overwrite" any existing files, as long as you use the same download folder you used on the other attempts.
If I were having this issue, I would first try rebooting and then attempt to download again. If that didn't work, I would try a different browser, such as Firefox. I usually use Firefox for downloads anyway, because they are faster with that browser. The reason for this is Firefox is a very basic browser. While it is highly customizable, even with a few toolbars on it, it is still much smaller than IE and because of that size difference, downloads are faster. I found a difference of 50kb in download speed between IE7 and the current version of Firefox.
If I were unsuccessful I would then try downloading a package from a different website, (you can always simply delete the package, if you are using the Save and not the Run option. It is always best to use the Save option, which allows for saving the download package to your hard disk, then if you ever need to do a repair or remove/reinstall, the package is right there) and if it downloads without an issue, (try to locate a file of similar size, try looking at http://www.cnet.com/downloads) then it is an issue of the Grisoft website, not your browser.
If you find it is the fault of the Grisoft website, try waiting to a time when the Server is not as busy. Sometimes if a websites Server is really busy, downloads can be very slow, or be interrupted. Waiting until a less busy period, such as during the early morning, or late evening or even late night, you may be successful in your download.
Good luck and I hope you get your anti-virus application downloaded and installed soon. Please have a nice day.