Sorry to hear of the situation. Social Phobia can certainly be a very distressing problem to have. Before I proceed further can you tell me what treatment approaches you have researched or read about and what your reaction to/feeling about them is (so that I don't start describing things you already know about or don't wish to consider).
Ok, thanks for the extra information.
As you've found breathing techniques can be helpful but they rarely cure social phobia. Cognitive Behavioral Therapy (CBT) is widely regarded as the gold standard therapy for social phobia and it is usually very effective. CBT is a psychotherapeutic approach that aims to solve problems concerning dysfunctional emotions, behaviors and cognitions through a goal-oriented, systematic procedure. Treatment is technique driven, brief, direct and time-limited (normally 10-12 sessions). CBT is used in individual therapy as well as group settings, and the techniques are often adapted for self-help applications. I would strongly recommend that you consider CBT as I would expect you to get great benefit from this approach.
Start by working through this excellent CBT based self-help program here http://www.cci.health.wa.gov.au/resources/infopax.cfm?Info_ID=40 . It should take you several weeks to work through and will teach you everything you need to know about Social Phobia and how to use CBT techniques to bring the problem under control. I use this material with patients regularly and I find the material to be really helpful.
If after working through the program you find you are still having difficulty then I would recommend you consult with a CBT trained therapist for assistance. CBT is usually offered by Psychologists (although not exclusively) and you can contact The Australian Psychological Society for assistance with finding an appropriately trained Psychologist. Take a look at the APS locator service here - you can use this to find a Psychologist in your area and there is a phone number you can contact if you want a referral arranged for you. Also, take a look at an article published by the American Psychology Association here. It's an interview with a senior Psychologist and covers some of the things you should consider when you looking for a Psychologist. You should also be aware that Medicare subsidizes sessions with a Psychologist in many circumstances, so you may be able to get some help at little to no cost to yourself.
I hope this has been of some help. Please let me know if you have further questions or would like me to clarify any part of my answer.