Their is your linky. Other people are too lazy to copy and paste.
Generally, its up to you and what games you play and what you plan to do. Most people love the Xi-Fi that they get when they are heavy into the EAX games and music/dvd.
As for how would it hook up, If you want to use EAX, the soundcard itself would need to be hooked up just like you have it now. Most soundcards work about the same on the outputs. Unless the device (your speakers) supports EAX, bypassing the onboard hardware would put all of the decoding load on the speakers digital decoder, witch it does not have.
Thats right. If you get a little lost, just look in the help booklet that comes with them. Since that is a 7.1 card ( I have only worked with the 5.1) you may need a special Mini-RCA dapter that is for 3 channels (someone correct me if I am wrong). I would check into that first. Going to the Xi-Fi from a Live is a nice jump.
-Edit: Also, I dont know about your speaker selection where you live, but before you drop a whole load of extra cash into the big boy sound card, check out something from Klipsch for some higher quality speakers.