In two weeks you are pretty much where you are. You can perhaps look at/ride the course and plan out your gearing, cornering, etc to maximize what you've already got.

I'm assuming it's a non-drafting event - so in effect a 25 mile time-trial...

My approach to a 25 was quite simple... As it's a relay, I'm guessing you don't have a "start time" so can't warm up properly, but do try and ride yourself in a bit if possible. Go out at a reasonable pace, not full gas, but maybe around 85% for a couple of miles, then "just" wind it up to just short of blowing until the last mile or so. Then give it everything... You should basically expire 2 yards from the line and maybe have the breath to shout your number or tag your relay partner. Have someone on hand to catch you as you fall off the bike, pick you up 5 minutes later when you're no longer purple/blue, and hold your hair out of the way while you throw up.

if you have access to a decent trainer, do a ramp test asap (to give you time to recover from it before the race), find your 1 hour threshold, and ride to 95-98% of that - either by preference with a power meter, or failing that a good HRM. Don't worry about the speed, just worry about riding as hard as you can, and the speed will come. I'll not lie to you though - it's going to hurt! Enjoy :laugh:

1) As Scott said, check out the course, ideally pre-ride the course in early AM when there is little traffic. Think about how you can safely get through the corners without having to scrub much speed (typically scrub some speed before the corner).
2) Wear a tight jersey...assuming you'll be able to stay above 20mph, aerodynamic drag is your enemy. Don't wear loose cycling clothes that will catch the wind (why racers wear skin suits when they time trial).
3) Ideally, you would want to use aerobars, but if you have never ridden with them before, two weeks is not long enough time to become proficient on a course that may have corners. Second best solution is to ride in the drops as much as you can, again, the purpose being to reduce drag (resulting in more speed for equivalent power output).
4) Be well hydrated before the race, and if possible only go for a bottle once or twice during the race. Each time you grab the bottle you are scrubbing speed and losing time. But absolutely drink if you need to drink. You should not need to eat during a 40k (25mi).
5) Know the rules. As Yin said, this is likely a non-drafting tri, which means there are rules related to how closely you can follow other bikes, and rules related to passing other bikes. There are also very strict rules in the transition areas related to having your helmet fastened, and often a well-defined line where you must dismount from your bike prior to entering transition. Know exactly how you are going to transfer you timing chip from you to your runner...you may want to have the swim team member actually do the transfer from your ankle to your runner's ankle (if not prohibited by rule). Know exactly where your runner will be standing after you re-rack the bike and run over to him or her at team transition (where your runner will be depends on how the tri organizer wants to set up the race...just know where they will be at).
6) Check out your bike two days before the race. Make sure your tires do not have significant nicks or cuts that may result in a flat during the race. Tighten the bolts on the bike (cranks, chain rings, deraillerur brackets, seat tube collar, etc.).Make sure the chain is lubed. Do not make any significant changes to the bike set up prior to the race (ie. adjust the saddle, new shoes, new pedals). Make sure your cleats are not overly worn and are tight on your shoes.

Good luck, be safe, and have fun!