You got ansfer for the first question.
For the second question, how to know your "outside" IP, the one you got from you ISP, you could use tracert command.
assuming that your box is directly on your router/firewall it would look like this:

>tracert www.yahoo.com

Tracing route to www.yahoo.akadns.net [216.109.117.106]
over a maximum of 30 hops:

1 time time time 192.168.0.1 <- internal IP of your router
2 time time time xxx.xxx.xxx.xxx <- external IP of your router
3 .....
4 ...

and so on

take a shot