Go to
www.no-ip.com
Register for their free service.
Once you have an account with them, go here:
http://www.no-ip.com/downloads.php?page=win
Install that. Keep it running,and just set it to how frequent you want to to update your IP. Like every minute, every five, etc... It will keep your IP current if it's always changing, or disconnecting.
Or, you could always try one of those stay connected apps.
Something like this, or software similar to it:
http://stayonpro.com/