Open the deleted folder and highlight all of the deleted calendar items, right click and select move to folder and choose the calendar folder and they should all be back. Alternatively drag and drop them to the calendar folder.
Restore points would not help as this doesn't affect data.
For sync with my Samsung Galaxy S I use Google Calendar Sync. This syncs Outlook with Google Calendar and my phone is then automatically updated. You can set it up as updating both ways or one way only.
Have you used Kies? This will update the phone's calendar but not the google calendar on your phone. Both display in the calendar app. I choose not to sue the phone calendar.