I am sorry to tell you that your camera is NOT an HD camera - so you will not be able to work with HD video. Here is the specs for your camera - then I will explain and offer some advice:
Format: SD (MPEG2)
Video Signal: NTSC color, EIA standards Inputs and Outputs
Analog Audio/Video Output(s): Included (via A/V Remote Terminal)
USB Port(s): Hi-speed (2.0 compliant)
S-Video Output(s): Sold separately (via A/VRemote jack)
Audio/Video Remote Terminal: Video / SVideo / Audio
Alright - as you can see your camera format is only SD - standard definition. This means that your camera came with an Audio / Video cable that has a Yellow/Red/White connector on one end - and plugs into the camera on the other. This is your output. It will resolve to 640x480 resolution, which is 1/8 the size of your computer screen. If you BLOW IT UP on the computer - it will look absolutely horrible - so you will have to lower your computer's screen resolution when you broadcast - easy enough - right-click desktop - settings - change display.
However this also means you are only capable of capturing SD video and that means you only need an SD capture device. I recommend MATROX because of it's affordability and scalability. Meaning - if you buy an HDV camera - you will be able to use it and get an instant picture upgrade to your broadcast. Also, because it comes with it's own capture software, and you will not need to have any other special software.
In Summary - You need SD capture - the video will be displayed on your computer monitor, and the audio will be heard in the computer speakers. This will allow you to then transmit the video signal out past the laptop using the built-in distribution for the laptop video and your audio will take the same path it uses now.
That's about it.
Thank you. I value your business.