I used her IP adress to find her computer but no luck
Typically the issue with home (or business) setup is that you are both behind "network address translation" routers, that "change" what IP address you are on, and don't usually allow someone from "outside the home network" to get directly to the other computer. But no worries, as mentioned before, the "Team Viewer" products works great, and is free (for non commercial use). I love it.
Also, DropBox makes for a super easy way to share files between you and someone you trust. (I'll just put my referrer link right here: http://db.tt/D5BQcbf