You could extract the data into a similar table without the auto_increment field, add your records, sort into date sequence then drop your original table, re-create it and then load the data back into it.
Alternatively you could just add the new records at the end, index the table on the date field and query the table with an "ORDER BY datefield".
The auto_inc field just ensures every record has a unique id. You don't always have to extract them in that sequence.