Ok so forgive me for being a dumbass but I over looked one major aspect in my setup....
After looking at the architecture posted above I noticed that I do not have a Switch connected to my Core...
All I have is a router with built in wireless connected to my core via CAT5!!
This means I have to buy a second ethernet card dont it!?
Any ideas on the best one to get??
Thanks for pointing out my stupid error!!
The standard supported configuration is 2 x nic's in your Core. One Nic, the WAN side, faces the outside world and your broadband connection and the other faces your internal LAN. The WAN side Nic gets its IP address from your broadband router (either a fixed address of your choice or one offered by the broadband routers DHCP server). The Core's LAN side Nic issues DHCP addresses to all devices on the LAN side of your Core (Your Core must be the DHCP server for the LAN - this is 100% essential).
See the Wiki for supported PCie LAN cards - look in the 'User Setup's page http://wiki.linuxmce.org/index.php/Category:User_Setups
All the best