I don't think you're going to be able to tackle this sort of thing without first getting therapy for your social phobia in-general.
Approach anxiety is something that even socially comfortable, confident, guys struggle with from time-to-time, so someone with your (our) kind of anxiety is going to have an especially hard time with it.
I'm afraid that if you try to ask a girl out in your current state, your nerves are going to get you shot-down bad, and you'll do serious damage to your self-esteem.
Upon further reading, I’m thinking this might be a troll, so I reserve the right to copy-pasta this awesome advice the next time someone asks this same kind of question.