Edited by Vitamin Ski - 5/18/11 at 6:29pm
Errr, forget the supplements and get some interval work in? (I'm just getting that out of the way so you can get some serious answers)
Second the Water Boy comment- lots of liquid (that is non-alcoholic and non-carbonated)! Many people often confuse dehydration with altitude sickness.. On a trip to Vail/ A-Basin a couple of months ago, most of our group members (all from your area) felt alright by the second or third day even though our condo was at about 10,000ft.
Nothing but training can stop you from feeling winded. The sports drink you mentioned sounds like a fancy Gatorade drink with random vitamins and herbal ingredients. While some may swear by these products, you don't know how you personally will react and so I'd advise taking anything that you haven't used before your race.
So while you're going to be sucking air, you can fight the general feeling of malaise caused by your cells getting less oxygen with by treating your body right.. As an athlete you probably know all of these things- such as eating well (proteins and carbs, chocolate milk/ bananas for recovery snacks) and staying hydrated.
Good luck and have fun!
When deciding if you have drunk enough fluid check for the 2c's clear and copius. Also a friend of ours who is an er nurse recommends drinking a protocol of 8oz of water per hour followed by 8oz of gatorade doing this for 8hours for a total of 64oz. Do this starting the day before the trip to start and continuing the first couple of days while arriving and this takes care of most problems when visiting Colorado.
Good Luck at nastar.