Bad news is you really can't replace the onboard LAN if it's actually "Broke"
Good news is... The Green light signifies it see a good link and the Blinking Orange means it's getting/sees traffic. So I don't think the port is bad.
What happens if you go to a command prompt and type IPCONFIG? Does it show the correct IP address scheme and correct subnet?
If it doesn't try typing at a command prompt IPCONFIG /RELEASE then IPCONFIG /RENEW to see it pulls the correct IP address.
Let me now if any of this works.