Information used by your employer on the TD1 tax withholding will need to be duplicated on your tax return to calculate the correct amount of tax owing/refund for the year.  In Turbo Tax desk top software use the left hand menu and select "Deductions & Credits" > "Payments Profile" > check the box for "Paid/alimony/child support and then continue. 

Select "Yes" you paid support, on the data input screen provide the required information. (You may not have your spouses SIN). Make sure to provide the total of all support payments made during the year and then the amount that will not be deducted on the tax return (child maintenance payments).