I have to include my spouse's returns, more specifically her "net income", or line 23600, but I dont know how to find that info

You can find it on the T1 of their tax return.

You can see a detailed summary of their return in the online edition of TurboTax by following the instructions on this TurboTax FAQ: How can I see a detailed summary of my return in TurboTax Online?

If they have not done their return yet, you can enter an estimate for now and then put in the actual number when you file.