How is your box connected to the internet? ISP? If the ip
address is assigned dynamic, it going to be deficult.
Frist use ssh not telent you can find a client for windows here:
Redhat installs a firewall, by default I believe telnet is turned
off , unless you told it otherwise on the firewall setup screen during install
That being said the command are as follows:
ssh -l username domainname
or you can specify a hostname.domainname