1. The WinTV-Go is the bottom of the barrel as far as TV cards go. Just getting a picture you can see, is really worth the $45 dollars that the card costs.
2. I'll assume you are using the coax cable connection from the VCR output to the TV card coax input and reading channel 3/4. Well, what can we say, the VCR is decoding the tape, vhs quality

, and then, your 45 dollar TV card is encoding (probably MPEG-1)

, to your computer montor, via overlay

. A horrible thing.
So, even though you are seeing 'low' quality, it's a blessing you are seeing anything at all. I'm not talking down to ya either, as I have one of those wintv-go cards also.
But you can try some of the 'new' type of TV cards, or high end vid cards with TV capabilities built in. See
http://www.linuxlogin.com/linux/wintv.php . Maybe the application you are using is not so 'good'. See
http://tvtime.sourceforge.net/ specifically
I didn't know that the wintv did SECAM that well, anybody else 'have' hands-on experience to help with that???