Since it was also a rental property, the sale should be entered in that section. You will prorate the space like you have always done. (duplex) Continue through all the screens noting the sale.
Treat this as two separate properties. On the rental side, you pay capital gains tax on the entire gain, including depreciation recapture. On the part that used to be a personal residence, you can exclude 250k/500k,
You will be asked in the latter part of the interview if it also was a primary home.
