analog video capture

Greetings

I like digital video editing and I have an Asus riva tnt with video in and out; when I want to capture a sequence, I am limited to 352* 288 points because at the next resolution (nearly 700*500) the frames per second that i get are around 10 fps.

I was thinking of buying an alone capturing card in order to capture and I doubted between buying one of these of television that cheaper ([chip] bt878, etc.) or one more professional like miro dc10 but its a bit expensive, what I want to do is to capture at resolution a little bigger than 352*288; does anyone can recomend me what to do?it wolud be worthwhile the money for the dc10?

my computer is a pentium 2 400 on a QDI advance 5/ 133 (via apollo) motherboard the hard disk is a seagate 10.2 gb ultra ata 66, 128 mb of ram at 100 mhz

if anyone know a web page about video editing, please tell me

sorry for my bad english