You'll have to look for your card driver and figure out how to compile the module and load it. This
link might help you figure it out.
It might be easier if you were using a newer distribution. Red Hat 9 is circa year 2000 I think. It's probably running a 2.4 kernel of some sort, which mostly isn't supported anymore. I think they're up to 2.6.19 now, so almost all drivers you find today will be written for a 2.6 kernel...
I use Debian Etch and
MythTV to use my tv card.