I am THIS CLOSE to buying a new bike: HELP ME

I have completed my first sprint and olympic tris this year. In both events I finished in the top 50%, which was my goal. So, I have decided I enjoy the sport enough to get a bike (I have been borrowing an old Trek 2120 that is way to big for me).

I am planning on going to All3Sports in Atlanta to buy the bike, but would like some answers for general questions prior to my visit to the showroom. I am planning on a full fitting with their f.i.s.t guy, so I am sure to get a bike that will fit me. That said, I would love some input from you guys.

My budget is $1500-$2500 MAX

1. I do most of my riding and training alone, but I do live in an area that is not exactly flat (Gainesville GA). I plan on competeing in an olympic distance race once a month during this season and next season as well. So first question would be: Is a dedicated tri-bike right for the kind of riding I plan on doing.

2. My goal was to complete a 1/2 IM next year and a IM in 2009, but I am ahead of schedule at this point and may try to register for a late fall 1/2 this year and possible IM in 2008. So question #2: If I am planning on the longer distance races is full carbon that big of an advantage vs. aluminum. I am looking for comfort more than speed. My goal is to finish the races in decent time, but I am not looking to compete with the elites (not yet anyways!).

3. Window shopping so far has led me to the following bikes.
1. Kuota K-Factor (Adv FULL CARBON) I really like the reviews on this bike
2. Cervelo Dual (Adv Price)
3. Cervelo Soloist (Adv flexibility can use for group rides if I decide I enjoy that).

So question 3: Any input on the above bikes or recommendations of other bikes that might fit my needs would be very helpful.

4. The K-Factor is full carbon frame but only comes with Shimano 105's while the Dual comes with Ultegra componets. What is more important the frame or componets?

THANKS!