There are some other things you can do before investing in a road bike. They are minor, but overall it might make a little difference. Get your bike fit, even a hybrid, if your shoulders are fatiguing in an upright position, you may need some help fitting the bike to you. Any local bike shop can do this. As others have said, clipless pedals will give you more power. There are some that are very easy to clip in and out of on the lower end of the price scale. Ask the guys at your LBS what you can do to your bike to make it lighter. If you haven't already, get some slicker tires put on. You are doing awesome, good luck on your tri.

Jen L