For a small firm i'd stay away from a business broker. Sure they have a template and they could crank your financials through and help put together a package, but you or your buyer are giving up a slice of the pie for no reason. You'd be better served reading a good book on negotiation

I bought out a business partner some years ago. different industry, but I consulted a good corporate attorney. He helped me put together a nice buyout and saved me a ton of money. You obviously want yours to go the other direction, but same principle applies.

Is your buyer interested in anything more than your client list? Are they print and marketing focused and want to boost their web game? Is your team more valuable to them than your client list? How bad do they want what you have? Would they consider you retaining a % of ownership to assure that the transition happens smoothly and business grows, or do you just want to take the money and run?

How many years have you been in business? What's your EBIDA? What does your 5 year business plan look like? These are all questions that your buyer will want to know, and a competent accountant or corporate lawyer will be able to help you make look good as possible.