I'll be there around the same time. I'm in the process of arranging 2.5 weeks touring around the island. I'm in contact with a local travel agent service that does private tours with your own driver and car. It appears that this is the best way to get around and it's not too expensive. For my 17 day trip the car and driver/guide cost is just a little over $1K. Hotels are on top of that.
With just 5 days I'd guess you would want to select something like the cultural triangle and Kandy. The incomparable DanielW's recent trip report might be of interest to you
http://www.flyertalk.com/forum/trip-...sri-lanka.html