Here's a good link to super bowl tickets info in general. I believe the fact that the game is in Detroit will diminish the value just a bit so I'd guess the nose bleeders will be in the 400-500 range. To get those prices you better find yourself a season ticket holder though because they only ones paying face value will be season ticket holders.
http://www.ehow.com/how_3895_buy-super-bowl.html