Moving email server from existing server

I am currently administering a server that is connected to a HP Procurve Switch 4000M which is connected to a DSL router. Since it is coming off the switch it has an IP of 10.1.0.10 and a subnet of 255.255.255.0. Further we have a PC running in another room that has an IP of 10.1.0.2 which is dialing up on a phone modem and pulling down emails using a software package called Software 602. We have exchange server on the Win NT server that sends/pulls the emails from this dial up PC. This dial upPC acts as our POP3 and SMTP. I would however like to just use the server’s exchange server to do all of this rather than rely on the dial up PC to do all of the email management. Can someone offer a suggestion how I need to set this up?