How do I avoid paying income tax on a severance payment for Medical Insurance Premiums that should not be taxed?

After being laid off, I received a lump sum severance of 20 weeks pay and 20 weeks continuing medical insurance premiums. I used the money to pay the premiums and thus I should not pay taxes on the money. But both the pay and premiums were reported on my W-2. So how do I deal with this in Turbo Tax so I don't have to pay taxes on it. Do I just adjust the W-2 Box 1 to subtract off the premium portion of the payment? Or something else?