I'd recommend you do some research on different web design companies and see their rates and what they can offer you. What you are attempting to do is slightly complicated and delicate, since you are handling credit card information :).
Describe your situation exactly and what your main points are you hope to get out of their services. Be a smart customer. If you can't afford it, you can look into premade shopping carts and templates, though you still will have a lot to read up on.
I know that if I was going to buy something, and the website didn't at least look decent...I wouldn't trust it.