How did I not see this before? Gosh.....
I would go for a P3C or a P2. You just can't go wrong with those - check eBay or the classifieds at slowtwitch.com for the best deals. For the fork at least have a 3T Funda, but if you want to shell out the $$$ then get a Cervelo FK26 fork. That's the one made for the P4 but now comes on the new P3 and P2 and also the S5. That fork will save 5 watts over the Funda and the Funda is 5 watts faster than just about anything else.
For the aerobars nothing beats the 3T Ventus. On a budget though I'd try to get anthing Hed. USE Tula bars are pretty amazing too. Equipment wise that's about all that is really important. Be sure that you have a good skinsuit - preferably a Nike SwiftSpin suit. Check eBay. I think the data was that it will save over 1 minute in a 50k TT over a regular skinsuit and that was at "Lance speed", so that's about 1 minute over 40k for us mere mortals.
What do you have as a helmet? Helmets are very personal depending on your riding style, but my favorite is on old LG Rocket. You can find them cheap on eBay. Get some rigid insulation and use a Dremel to shape it to fit inside the tail. If you are really feeling frisky then get some ~1/2" foam insulation and cut a 1/2" wide strip. Tape that strip to the front edge around the front of the helmet (so it's around your forehead and sides of your face). Then use the dremel to curve the outside edge. That cleans up the airflow between your face and the helmet. Or just toss a visor on. It will be faster than any other helmet out there. Or you can pay $$$ for the Giro Selector - that's fast, but I couldn't get it to fit me. Also I have heard it doesn't ventilate well, so I am not interested.
Work on your position to get your back as flat as possible and practice riding with your chin "down and out" so that your position is good. For me this means my saddle is really far forward and the bars are REALLY low. My power in this position drops, but the aero is so good that I am WAY faster.
Gosh, not I am modivated to get Victoria set up for some TT rides. Thanks!
Have you ever wondered if there was more to life, other than being really, really, ridiculously good looking?