Looking to Upgrade Components on Raleigh Sport Road Bike?

I have a Raleigh Sport Road Bike (2007). An image can be found here http://answers.yahoo.com/my/my;_ylt=AoSN... of my bike.

I am new to cycling and I know that my road bike is more geared towards beginners but I am rapidly going from beginner cyclist to more of a competitive racing cyclist. I am by no means in the same weight category as most cyclist but am very muscular adding to my weight.

With this said, what are some of the first components i should aim to upgrade first on my bicycle. Should I get new wheels, should i get carbon fiber forks, carbon fibery handlebars, new derailer, etc. Also if something seems to be more expensive than the other i am very much intrigued.

Thanks
Randy

sorry the link to the bike is here : http://www.auctiva.com/hostedimages/show...

Without a doubt the first upgrade I would get would be clipless pedals and real cycling shoes. Second would be lighter more aerodynamic wheels. Other than that, I would save my money for a better bike. It is a lot cheaper in the long run to just get a new bike with better components already spec'ed than to upgrade piecemeal on a low end frame. Also, better pedals and wheels purchased now to improve the ride quality of this bike could easily be transferred to a better bike in the future. Swapping used derrailleurs and such from one bike to another is not so easy.

clipless pedals, lighter tires and tubes. lighter saddle. most other upgrades are very expensive if your main goal is speed--which i think means you want to take weight off the bike--right. spend a little money on these upgrades, run that sucker into the ground and then buy a better bike if you are still "into" it. keep the old bike for a trainer or backup.

If you are a heavier rider you could try some good tyres -- perhaps in the slightly wider 28c size. E.g. Continental Ultra Gatorskins, which are very popular and quite puncture resistant too, plus they ride very well. The wheels look OK but a more aerodynamic front wheel will let you go a bit faster. It is also important to find a saddle that you find comfortable -- you need to try a few out at your local bike shop (LBS).

I would just replace the groupset items (deraileurs, shifters, chain etc) with new Shimano 105 items when yours wear out. These are great quality, but the ones you have are OK and there is little sence in replacing perfectly good components.

I would however advocate that you experiment with saddle height and handlebar height. Your LBS will show you how. Most beginners have their saddles too low and their handlebars too high.

Well, if you are looking to upgrade, I hope you are ready to spend some cash.
I started with the most expensive stuff first which would be shifters, wheels, and fork. Then I went to the drivetrain, derailleurs, cassette, chain.
The next stuff is what I consider optional depending on how racey you want your bike. These would be the cranks, stem, handlebar, seatpost and saddle. Tires are last. I really like the Michelin Pro Race. Smooth ride! Don't forget the headset. Chris King is the best unless you have integrated headtube which then I would go FSA.
Hope this helps. Good luck!
I forgot to mention CAMPAGNOLO is THE best. It's all I ride.
Shimano is.......ok. But I'd stay away from the Dura-Ace line. Not very durable.