Atmel MEGA128A Ethernet Interface Added(repost)

I have an existing project that uses a GSM modem via AT commands to access the internet. I need to code changed to use an Ethernet interface to connect to the internet. The hardware is designed and I have a prototype PCB built ready for testing. The current project checks the status of an RS485 device, and uploads the data via the internet to a server, the server is also used to configure what RS485 devices are scanned. This is all working via the GSM. I just need the GSM interface exchanged for an Ethernet IP interface. It will need to support DHCP and Static IP, and can be configured locally on the board via either a web interface or Serial port. The hardware is a Atmel MEGA128A and a MicrpChip ENC28J60 Ethernet controller. This is coded in C ENC28J60