Setup Mac OSX Server (10.6) and Airport Extreme DNS

We have just purchased a Mac Mini Server with Snow Leopard OS X 10.6.3. We have the server set up within our network but are having difficulty with access and management outside of our network. We currently do not have a static IP but we can get one within 1 - 2 days. Alternatively we are open to using DynDNS. We need someone with knowledge of OS X Server to configure the server settings as well as our router settings (Airport Extreme) for optimum use. We do not use the server for hosting sites or email, but we want to use many of the other features (iCal, iChat, file sharing, wiki server, etc). We are open to suggestions and how to make this operate as efficiently as possible. This project needs to be completed within 7 business days. An individual with proper working knowledge should be able to complete the project within a day.