Dscaler (
DScaler - TV & Video Deinterlacer) is basically an alternative to whatever software your TV tuner would come with. It has some added stuff like deinterlacing and video filters.
So, you'll be hooking up the PS2 to the TV card, and running dscaler to view the video. The sound will always be "on" as it's heard through "line-in" (at least with my config).
And a side note, I wouldn't worry too much about the resolution capabilities. Don't forget the majority of PS2 games are 480p (640x480), and half can also do 16:9. Forcing a higher resolution would only stretch everything out. To get higher quality, you'd have to use something like PCSX2 to run the game.