Question about HDMI and DVI

Sorry for a basic question, but I'm not very well versed in computers. I have a fairly high end desk top (custom built). When my monitor went on the blink I bought an HD TV instead of a computer monitor. Specifically, a Samsung Series 6 630 Full HD LCD 40" LN40A630. I connected the monitor to my graphics card, a NVIDIA GeForce GTX 2951792MB with DVI cables because the graphics card did not have an HDMI port (I know that model is suppose to have an HDMI port, but whatever the custom builder put in doesn't have that port. I know it is an NVIDIA GeForce GTX 295 because that is what shows in device manager).

My question: Is the picture quality difference between HDMI and DVI great enough to be worth buying a new graphics card and cables? I do gaming and computer art work. The current picture quality is okay, but nothing eye popping.

Thanks!

In case it makes a difference, computer configuration is:
Motherboard: Asus P6T Deluxe
CPU: Intel Core i7 2.93GHz 8MB
RAM: 6 x Kingston ValueRAM DDR3-1333 2048M
Video Card: NVIDIA GeForce GTX 2951792MB
Monitor: Samsung Series 6 630 Full HD LCD 40" LN40A630
O/S Hard Drive: Intel X25-M 160GB SATA II 2.5inch SSD

There is no difference between HDMI and DVI as far as picture quality goes as they are the same technically. The biggest difference between the two other than the connectors, is that HDMI and pass audio as well as video.

Thanks a million for the quick responce! I really appreciate it.

i picked up one of theys off new egg works great on my 36'' 1080p tv when i am playing Battlefiels 2 is all that
Newegg.com - Rosewill - HDMI to DVI Cable (24+1) - 10 FEET

Resolution is 1920x1080 (the recommended resolution).

Thanks for all the great replies!