There are many ways to get EPG data into MediaPortal (I assume you are using standard MediaPortal not TV-Server). I use
XMLTV GUI Grabber. This is scheduled to run at 5.30am every day. It can also be set to post-process the xmltv file to change the channel names. Now all you need is to tell MediaPortal where the xmltv file will be. There are many other ways, the advantage of this one is that you don't have to do any repeat setup if you reinstall MediaPortal.
Your KWorld DVB-T 100 PCI card (I assume that is what you meant) is a digital terrestrial only card, you will need to buy a hardware encoding analog card to connect to your Virgin Cable box.