1. ATI's Radeon range (ie Radeon AIW) do cards capable of capturing composite/SVHS signals. This area ain't my speciality though and on your budget, you may be able to opt for a better card.
As for capturing DVD's, rather than 'capture' the video, thus the quality is determined by your capture device. Your much better off 'ripping' the DVD from the disc using a DVD-ROM drive. This way you get a faster capture, less room for error and 100% original lossless quality. You then have a pure file to play with as you wish. For more help on DVD ripping, converting etc check out
www.dvdrhelp.com.
2/3. 'Capture from ripped VOB's' not sure what you mean here. For editing Adobe Premiere is the standard choice in the mid price range and yes you can get this bundled with cards alkthough maybe not in your price range. You could look about on ebay for a second hand copy.