i have that same ati tv card. you need to get a good ati video card to go with it. they don't say that in their advertisements. i had to buy one. tiger direct is the best source if you're worried about price. also the quality of your sound card believe it or not plays into it too. sound cards have an internal clock, (not a clock you can see). the better the sound card, the more accurate the clock, the better your stuff comes out.
http://www.tigerdirect.com/