Im running it on intels hd4000, im getting a 680gtx next week but for now im stuck with Igpu. How do I check the tv resolution?? All I did was plug in the hdmi and it was good to go so I didn't bother checking
I'd stay with Tom's HW for answers as most of the users are into computers and know what they are talking about.
A GTX 680 and a GTX 670 will run guild wars fully maxed out at 1080p, with no problems. The GTX 670 will offer better bang for your buck, and nearly all cases will max out a game at 1080p whilst maintaining 60fps.
Onto your 2nd point.
Nvidia are the people who make the actually chips that go into a graphics card, and will release a reference design to 3rd party companies like Asus, MSI, gigabyte, EVGA, zotac etc. who will take the design and add their own cooling solution, change the PCB layout, add extra bits for more stability, increase the amount of VRAM and overclock the card. The performance of the different cards from different companies varies a bit, however they'll all be better or the same as the standard card. When it comes to choosing, you can't really make a bad decision as long as you stick to a reputable company. If you need help tell us a card you're looking at and we'll tell you if it's any good, or whether you could get something better.