You [i]need[/i] to press charges. If they have a written confession from the guy himself, it's time to end this and follow through with pressing charges. You're an adult -- you don't need to have your family behind you on this one. It's time to take a stand for yourself, regardless of what they whether they want you to keep quiet or not. By holding your silence, you're allowing this creep (and whoever else is involved) to potentially go do these things to someone else. 

[i]You're enabling their behavior by not pressing charges.[/i]

Be brave -- I can understand how this could all be scary, but it's the right thing to do.