It can be easy to assume that your website is working for you, or take the usual stance that you know it is poor but don't get chance to do anything about it. A website is a shop window that crosses boarders and does not shut, so it would be hard to find any business that wouldn't benefit from a quality online prescence.
So, if you don't have a website you should, and to be honest it doesnt have to be expensive - you just have to identify what you regard the return on investment to be - online sales, phones enquiries, educating customers - or simple meeting the status quo of your competitors. Which is an interesting point - your competitors will give you the best indication of where you stand, if you are not comparable then you are going to get left behind.
Be careful though, the goal of any site should be to meet the goals set out and represent your 'real' world business and goals. Too often companies have a very disconnected view of the way the business communicates and what their website is doing for them.
So when you talk about marketing, advertising or branding - you have to consider what you are doing offline and how that effects and compliments what you are doing online.