If your tuner card works with Xandros then it will most likely work with any current Linux Distro. There are two types of TV tuner cards. One is for standard definition/analog (ATSC) and the other is for digital signals (DVB). It sounds like your card is only capable of standard def/analog (ATSC).
You mention that you want to edit video. Is this from TV that you have captured or from a camcorder or other video device? What type of inputs does your WinFast card have? It sounds like this card was made for Windows and you will probably find that all its features are not supported in Linux. Video capture from an external source and TV tuners are separate animals. For capturing video to my PC I use firewire connected to my DV camcorder. To capture analog sources I use a analog to digital converter from Sony.
For Linux TV tuner cards this is a good starting point:http://www.linuxtv.org/wiki/index.php/Special:Categories
I use a Kworld-115 analog/digital tuner card in my Mint-MythTV system.