IT business insurance

I have recently just started my own IT business,which offers
consulting, support,upgrade and repair service, and also new and second user sales. I have over 12 years in a technical support role involving hardware and software.
I have been told that I should take insurance for my business, which should probably involve public liability etc. Some business advisors have recommended becoming a member of an orginisation related to my business to get the best deal.
I would be really grateful if you could give me any advice on this matter.

Many thanks.
Des.

Des Mc Quilkin.
MCQ IT Solution & Services