I can't help you specifically as I don't have this equipment. Skype is
proprietary and it has its own video engine. Most programmes in Ubuntu have
Gstreamer as its engine for multimedia since that is what Gnome uses by default.
Some people find they get better results with switching to Xine for all kinds of
multimedia. I am not sure if this will resolve your problem, but I will throw it
in for what it is worth.

In the repositories you will see two versions of Totem. Totem which uses
Gstreamer and Totem-xine which uses Xine. If choose Totem by itself then you
will get Totem-gstreamer, I believe, but you can override this by installing
Totem-xine first. So you can try either or both and see if that improves things.
You can also install any number of pvr programmes from the repositories
including Mythbuntu. MythTV is hard to configure, but I have read that Mythbuntu
simplifies what is otherwise a hard thing to do. You can also look into Elisa
and Freevo plus if you search in Synaptic for TV you will find lots of TV
programmes.

I once had a TV card and it worked better in Linux than Windows, so there is
hope. I had to choose the chipset in the configuration and it worked fine.
However, your card is called WinTV and that usually means that it was
specifically made to work in Windows, like Winmodems, I suppose. They probably
have software components for Windows in addition to the chips that make it work.
This may mean that you need to find some equivalents in open source to get it to
work. I am firing blanks here because I don't have your card.