If you have a firewire card, and a Sony HC42 camera, you are almost there: converting footage you have taken with your camera to excellent dvd quality video on a dvd that plays in most free standing dvd players. You do not need a video capture card but you do need a dvd writer. Your camcorder has pass through which allows you to convert any AV material (VHS player, older analog 8mm, hi8 analog tape) to digital in your camcorder for input to computer via your firewire connection. Your HC42 is minDV, with your footage already in digital format on DV tape. You will need a 4-6 pin fireware cable to connect your firewire connection on your computer, but this is easy at any electronics dealer (cheaper at Newegg or Amazon online). You will also need a video editor package to handle capturing the video, editing it to keep the parts you want, adding titles and chapters as you wish. There are many capable packages out there for less than $100, but I can only vouch for the one I use and like. I use Arcsoft Showbiz DVD 2 because my MCE HP computer came with this software installed.
http://www.amazon.com/exec/obidos/tg/detail/-/B0001YM044/sr=8-2/qid=1139903138/ref=sr_1_2/102-2030995-5636927?%5Fencoding=UTF8&v=glance
Capturing video with the capture module is quite straight forward, as long as the camcorder is in the player mode, firewire cable is connected via docking station and the USB switch is in the off position. Importing consists on using the tape player controls that the firewire driver automatically brings up that controls the miniDV tape from the computer. You are given the option to name your video and capture it to a file in the folder of your choice. Editing the file and preparing it for writing to dvd is going to be your most difficult learning process. You have a story board view with the many clips you want to string together. You also have a timeline view for making titles, adding separate sound tracks. I found the easiest way to edit was to copy and paste the entire video footage to each of multilpe clip positions on the storyboard. Then you set the start and end markers on each clip to separate out each clip (scene) in sequence for the finished video. Set the transitions between the clips, and you are ready to write the video to dvd disc. You will need a dvd writer...best an internal writer connected to ide cable. They are not expensive but let a technician install it if you are not comfortable with opening your computer. I like the NEC ND 3550A which comes in black, beige, and white as an internal dvd writer.
http://www.newegg.com/Product/ProductList.asp?Submit=ENE&N=2000100005+50001326&Subcategory=5&description=&srchInDesc=&minPrice=&maxPrice=
Depending on the speed of your processor, it may take anywhere from one hr to several hrs to write one hour of video. Just start it before you go to bed if your processor is less than a p4. Most newer set top dvd players will handle both dvd +R,-R, +RW. -RW. Good luck.