I have network where internet access through router having fixed ip address (152.25.15.40)* and we have installed DNS and Active Directory to server (192.168.1.2) and default gateway to internet router (192.168.1.1), now we want to create website which can be accessible to outside office. we have already configured IIS.

how is the internet coming into your office? (T1, DSL, Cable?) the router will have to have port 80 forwarded to the internal IIS Server. The IIS box should have a static IP on your internal network so that you can create Host Header records for the site in question.