I don't know about getting into racing, so I can't help you there.
but.
I do know that the more you ride, the faster you get.
Also, ride with someone fast, once a week. Make it fairly short (15-25 miles) and chase them. That really helped me up my speed.
I also highly, highlyhighly recommend not dieting and training at the same time. When you are training, you are burning a bogus amount of calories, which is great for weight loss, right? Well, not exactly. Because you need to fuel the training, otherwise, if you just took the loss, you won't have any energy to ride. Kind of a vicious circle.
If you go into caloric deficit (from WW or any other diet plan) you should be careful to scale back your riding or running or other aerobic exercize to burn no more than around 200-300 calories a day. There's no real magic number there... it's just that you don't want to overburn and then go into starvation mode.
I don't know the science of this but you can get more info here.
You basically want to eat in a deficit of / exercize to only 10-15% of your maintenance - do slow weight loss (1-2 lbs a week.) To get your maintenance you can take your present weight and multiply by 15. That is about the amount of calories you need in order to maintain your current weight. Now take 15% off of that. That's how much you should reduce (either through exercize or eating less or a combination of both) in order to lose about a pound or two a week (which is the way to maintain weight loss - if you lose it slowly your body has more time to adjust.)
I lost 15 lbs this year in this way, before I started training. When I started cycling hard, I was eating about almost double my maintenance, just to maintain my present weight. If I had more to lose (I don't) I would scale back on the training and reduce my caloric intake.
Hope that is somewhat helpful... I'll be interested to read the answers about getting into racing as I too would like to race next season.