What strategy should I follow for lecturing a course in which I have only a basic background?

I am currently working in a faculty where among the courses in CS there is one about Computer Graphics. That course was taught last year by a professor who actually has retired, and who was a specialist in the field. The thing is that the Dean has talked to me for putting me in charge of that course in the undergraduate level, mostly because the other lecturers are with no available free time at all; and it will take some time to hire another professor.

The problem that I have is that even I hold a MSc in Computer Science, the knowledge that I have about Computer Graphics is basic. Only what I have followed in my bachelor's a long time ago.

Actually I am little scare of what to do, I have started compiling material for read and prepare my upcoming lectures, but I am afraid that maybe I will not be able to make a good course. In short, what strategy should I follow for lecturing a course in which I have only a basic background? Should I be completely honest in the first session and mention the students that this area is mostly new for me?