Modifying undersized road bike to be more comfortable??

I have my first triathlon coming up in September and I had to find a bike and I didn't want to spend a lot of money until I know whether or not I will continue with triathlons.

 I am a very big and tall guy at 6'6" so I knew I was going to have trouble finding a used bike in my size.....and ended up buy a used 56 cm Trek 1400 from a guy off this site.....I knew that was going to be too small but was hoping that it would be good enough to get me through this first race or until I could come across another used bike that would fit me better.

I road the bike this weekend and I can tell its not the height of the bike that is going to bother me....its the distance between the seat and the handlebars. I feel like the handlebars are way too close to me and I am putting a lot of force on my hands and wrists.....which is making it very painful to ride.

I was hoping that you guys may have some suggestions for modifications that I could do to make the bike a little more comfortable....nothing too expensive since I will be selling it again at some point when I find a bike that is bigger.

I am going to go get some good gel gloves today and hopefully that will help....I also saw where some bikes had what I think are called aero bars that attached on top of the existing handlebars....I thought these might help since I would be putting all the weight on my forearms instead of my wrists??

Any advice??