How to set one Ringtone for Contacts and another for non contacts? Is there an Android App that can perform one ring for anyone in my Contacts and another ring for anyone not in my Contacts?

I know how to go in and set individual ringtones, but I have 350 contacts.

Actually, all I would need is an App that sets a ringtone for any number that is not in my Contacts list.

If not, would that be difficult to create?
You can do this on android by going to contacts, then groups tab. 

You then need to click the menu button and create a new group. Give it a name and choose a ring tone then click add members and click select all (top left). This will add all your stored 'known' contacts to the group, and will use the selected ringtone for their incoming calls.

Anyone who rings who is not in this group will use the normal default ringtone. 

Hope this helps
Dan