Did your No.1 log book contain any ratings or type endorsements not contained on your licence? If so check with CASA they should have records of all your type endorsements and ratings.
As to the hours, one presumes you have carried forward your totals into the No.2 book. If you are required to substantiate any hours you can go back to your flying school/employer and check their records and/or you can make a statutory declaration concerning the loss of your log book.