I need some advice for a new video card for my pc.?

Here Are My current specs:



Dimension XPS 400, Intel Pentium D 820 (2.8GHz) w/Dual Core Technology



1GB DDR2 SDRAM at 533MHz (Upgraded to 3GB's)

256MB PCI Express x16 (DVI/VGA/TV-out) nVidia GeForce 6800

250GB Serial ATA Hard Drive (7200RPM)

Microsoft Windows XP Media Center Edition 2005



And this is what i want my pc to be able to do:

I'd like to be able to use my computer as a dvr, and while i can do that now, i'd like a videocare with an hdmi port as i have a hdtv. I'd also like it to have a dual tuner so that i can record 2 shows at once (if possile). Any suggestions or advice would be greatly appreciated. My budget is around 300.|||here are 2 links that you can go to. its best that you keep the tuner and the graphics separate for performance purposes.



http://accessories.us.dell.com/sna/produ…



http://www.novatech.co.uk/novatech/specp…



hope this helps!