NAT appears to be the default for Fusion, but bridged mode seems to work better for most people. Try setting to bridged mode and then running the network setup wizard if needed.
If it still isn't working, right click on My Network Places, select Properties, and then right click on VMware Adapter and select Properties. Select Internet Protocol (TCP/IP) and click on Properties. This will get you to most of the settings you need (IP, DNS, DHCP etc.).