According to the Hauppauge site you should be able to get QAM with that card.
http://www.hauppauge.com/site/products/data_hvr1600.htmlSo that card will work fine, but I don't think you bought the right card for what you want. Since you said you want to record HD there are a couple of ways to do this. You can use an antenna (and the 1600) and get broadcast HD channels. See this site to see what's available in your area:
www.antennaweb.orgYou can get QAM HD channels. These are the HD channels that are left unencrypted by your cable provider. You shouldn't need a box for these, just plug the coax straight from the wall into the tuner card. These channels are usually the local channels and a few others. You can get an idea of what's available for you here:
http://www.silicondust.com/wiki/hdhomerun/channelsThe third kind of HD is encrypted HD. These you can only watch or view with a cablebox (and usually some sort of HD package). The only way to record these channels is with the new HD-PVR and a component cable hookup.
Hope that helps clear things up for you!