Running at the rear

I am a runner....
I am a slow runner...my dream is to run in the middle of the pack. I am going to start trainng for my third 1/2 marathon and I would like to run it with out feeling like I am going to die. I would also like to complete it in 2hrs 30min...which would cut 13min off my time. I have decided to start eating healthy. I need to lose 40pds to be healthy and that would also help with my speed. I am also set to run the Around the Bay in Burlington in March I am signed up to the relay with two other runners who I don't want to let down with my slow ploddy gait..so I am going to try my best to be my best....starting today!!