Haven't read the entire thread yet (no time blah blah) so if I repeat stuff well to bad lol.
You probably want to change from a less social person to a very social person. First you must decide you want to change (obviously) than you can start working on it.
Now a couple of things first:
Body language; Standing up straight, shoulders straight, arms relaxed next to your body, head up high. Just pretend there a string on the top of your head running through the center of your body and than pull it a bit.
Voice tonality; This is a tough one, you probably need to learn to project your voice better. This means speaking louder and to not be affraid of being heard. For now just take note of this and leave it at that.
Some excersizes:
SMILE to everyone
Keep your body language correct at all times
Talk to 10 strangers a day, if you can't do this just say Hi to 10 people and make it tougher ones you can do that comfortably. Its best to try and do this to people of the opposite sex, you might as well get that out of the way.
Try and make the above conversations longer and more interesting untill the point you can talk to anybody anywhere for like 10 minutes. Don't worry about what people think about you, in fact don't worry at all...
If you can get all this down I'd bet you'd be suprised by the results.