Take a deep breath!
Find your book or look online. Get the part number.
Look in the phone book, online for sewing machine repair or call the store and get his name.
They can either repair or replace the cord. Bring the booboo cord with you to make sure you get the right thing.
Sewing machine repair shops have just about everything. I just bought a "new" cord and footpedal for my antique Singer. It cost $12.