Whiplash/ shoulder injury

Hi all

I had car accident in feb 2009. The other driver failed to give way at a roundabout and entered at speed sending my car sideways and forwards.

the other driver admitted liability at the accident scene. This has since been backed by the isurance company admitting liability, day after in writing. so no arguments on liability.

I was seen in minor injuries the same day with a 'burning sensation' in my neck, and a egg sized bruised swelling to my forehead. This led to five weeks off work. substantial neck/shoulder pain.
Since this time i have had ongoing neck should pain. A further three weeks off in jan 2010 when my neck went into pain spasm.

I have have been seen by medical practitioner (GP) - for initial report - he said recovery in 9 months......nope!
I was then seen by an orthopeadic surgeon - he said recovery in 2 and half years.
I have also been assesed by an orthopeadic surgeon (neck), by referral from GP. After MRI's and ultrasound, it was found that i have nerve impingement in my shoulder. Following two steriod injections into my shoulder ( which improved both my neck and shoulder) i have very recently undergone surgery to my shoulder. The surgeon has advised that i will be off work for 3 to 6 months due to shoulder intensive nature of my work. I have also attended psychological assesment for stress whilst driving and been diagnosed with an anxiety disorder. I am attending CBT sessions for this.

so there is the background. I am obviously awaiting recovery before i can settle my claim but in the mean time would like to ask some questions. My case is being handled by a solicitor appointed via my insurer.... BUT they are really less then helpful. it has already passed through several claims handlers. I have caught them lying on numerous occasions and feel that they have offered me poor support:

Questions
A) can anybody give a rough estimate as to amount of compensation - they are unwilling/unable to discuss this. and since i have had multiple issues  ongoing for above two year how can I guage the merit of any advice the give me on amounts to expect

B) interim payment - i am already Â?6000.00 out of pocket due to loss of earnings, prescriptions, physio ( paid for by me cos it took so long for the other side to cough up....i needed to get back to work) what are my rights cos i am seriously skint and off work again due to surgery. I have a mortgage to pay and only get statutory sick - part time and self employed partime so earn nothing there.

C) can i claim interest on the amounts i am out of pocket - this has depleted any savings  had - and the main loss of earning was two years ago.

Any Help would be gratefully recieved. Plus any future guidance acceptence
thanks