Sorry to hear of the situation, PTSD can be a horrible experience. I am dismayed to hear that you have been informed that you will never be rid of intense anxiety as this is a false statement. There are people all over the world who are able to successfully recover from PTSD and obtain significant reduction in the accompanying hyper arousal (anxiety) symptoms associated with the illness. You are right in being skeptical about the potential effectiveness of SSRIs in treating PTSD as they are not actually recommended for use in the treatment of PTSD. To be blunt, anybody who told you otherwise doesn't know what they are talking about. To reassure you that you are right on this matter please take a look at The National Institute for Clinical Excellence guidelines for the treatment of PTSD here.
I can talk you through the appropriate treatment approach for PTSD, recommend some reading you can do specifically on the treatment of PTSD associated with childhood trauma and provide you with some advice on how to locate the right therapist. I will stop here and wait for your response and any more specific question you may have before proceeding further.
There is growing evidence that Mindfulness meditation/grounding can be very helpful in managing intense anxiety, particularly when elevated anxiety is triggered by cognitive events (thoughts/reactions to something that has just happened). I would certainly encourage you to continue to develop these techniques if you are finding them to be helpful.
Cognitive Behavioral Therapy (CBT) is widely regarded as the gold standard therapy for trauma and I would strongly recommend a you seek out a CBT trained therapist for assistance. 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. The National Institute for Clinical Excellence recommends CBT for trauma and you can confirm this by checking here. You can take a look at this self-help guide here for an introduction to CBT for PTSD.I can also recommend this bookhttp://www.amazon.co.uk/Overcoming-Childhood-Trauma-Helen-Kennerley/dp/1841190810 as a good CBT based self-help resource for recovering PTSD related to childhood trauma.
You can contact The Australian Psychological Society for assistance with finding an appropriately trained Psychologist to deliver CBT. 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, if you have any further questions don't hesitate to ask. Best of luck!