Assuming the writing is still legible, get another logbook. Tally up the totals in your old logbook and transport these into the new logbook as the first line, or something like that. Put your signature next to it and a statement "hours flown from <date> to <date> - see logbook #1".
Not an option for the OP because he is currently training for his PPL - the logbook that is submitted to the CAA needs to show entries for each flight exercise endorsed by his instructor. Under other circumstances this is perfectly acceptable of course.