Get on the phone to your local highland dress rental shop. You already have the kilt so renting the rest should not be expensive.
Amen. And if you don't have a Highland attire shop that rents the kit, you could always get a short tux jacket (sometimes called a Captain's Jacket or Mess jacket) that doesn't cover the pleats and usually comes with a vest (stay away from cummerbunds wi' kilts -- never, never, never!) and a plain white dress shirt with a black bow tie, and you should be set.

T.