Work through the sale again. There's a "learn more" link next to "Fair Market Value on Date of Gift". Click it. It reads:

The cost or basis of property is usually the original cost of the property, adjusted for various items after you acquired it. Additions to basis include improvements you made to the property and nondeductible assessments for improvement.

Therefore you will add the cost of the property improvements you did, to the amount in this box.

If you click the "learn more" link next to Donor's cost basis, you'll see the same applies to this box also.

Thank you!  Also, should I adjust both the FMV and Donor's basis for the basis adjustments I made in the 18 years I've owned it?  If I only adjust the FMV for the basis improvements I've made, its still showing a large gain.

should I adjust both the FMV and Donor's basis

Yes. That's basically what I said in my first response.

I myself don't understand why the program asks you for the same exact thing twice, with two different questions.