I'm running a Cisco 1700 and it pulls two static IPs and forwards them to the appropriate internal IP using NAT.
The following should work on any Cisco router and will also allow other computers to do dynamic NAT on the fast ethernet0 interface. Make sure that you set the ip nat inside or ip nat outside on your interfaces
ip nat inside source list 7 interface FastEthernet0 overload
ip nat inside source static 192.168.1.80 <external IP 1>
ip nat inside source static 192.168.1.235 <external IP 2>
access-list 7 deny 192.168.1.80
access-list 7 deny 192.168.1.235
access-list 7 permit 192.168.1.0 0.0.0.255.