Hi and welcome to Just Answer!
You should not apply for new ITIN number. You may use the same number for filing taxes.If you filed your tax return - check copies - they should have ITIN.
For questions regarding lost or misplaced ITIN information - call the IRS _800_829_1040_ or _866_562-5227_ (Hours of operation are 7 a.m. to 10 p.m., Monday-Friday, your local time - except Alaska and Hawaii which are Pacific time.)
See more information about ITIN 's here - Publication 1915, Understanding Your IRS Individual Taxpayer Identification Number - http://www.irs.gov/pub/irs-pdf/p1915.pdf