If you want to access to a your personal computer from anywhere via "Windows Remote Desktop Connection" you have to: firstly, configure your modem. Secondly, you must know your IP. Here I assume that you know how to configure your modem (if don't please see here) then you should use a program like MailIP to send your computer's IP automatically to your email even if you have dynamic valid IP. In this way you save money from not buying static IP because when ever your IP get changed "MailIP" will send the new IP to your email. Also you don't need to subscribe to slow services like LogMeIn or TeamViewer and you can easily use the default windows remote control program.

The source code and binary file can be downloaded here.
MailIP