"My question is should i bring someone in to do this for me or can anyone offer me advice to help increase my confidence enough for me to do it myself?"
As you are running a business, I assume you don't have a lot of free time 'just lying around'? If that's the case, then it might be more economical for you to get someone else to do it for you, make sure to see a portfolio of their work though, there are a lot of well-meaning amateurs around with little design experience. Is the couple of days it will take to get it up and running worth £600 to you? Make sure you have the option to view the site and have some input on the site before you pay for it.
On the other hand, if you have the time and the inclination to do it yourself, go ahead, it can be great fun, a good learning experience and you'll get a lot of satisfaction when you see your own creation up and running on the web.
Have a look at the websites of businesses similar to your own, see how they look and work, then try to replicate how they were created. Look around the web, you'll get plenty of ideas, but don't go overboard, in web design, a lot of the time less is more.
If you get stuck, just start a thread here and ask for help, there are a lot of knowledgeable people here, only too willing to help.