Does this video card support sound?
Solution 1:
Yes, the HDMI output will provide audio to the TV (or monitor); all HD 4600 series cards support this. See this article for more info, or the ATI spec.
Solution 2:
Yes it does. All the ATI radeon (at least the 4xxx series for sure) comes with HDMI with sound. If you install the card and the driver from ATI, you will get a new sound card called "ATI" or something like that. Switch to that for movies/whatever you want to push out through HDMI and there you go. That's all.