First, if you qualified, turbotax would automatically add the rebate to line 30 of form 1040 unless you told the program you already received the funds. (In other words, you don't have to tell Turbotax to add it, Turbotax adds it automatically and you have to tell the program to take it off.). Have you checked your printed copy or PDF copy of your return? (It is not a separate payment, it is included in any refund you claimed, or it reduced the tax you owe, review line 30.)
Second, if you qualify and did not claim it on your tax return the IRS will automatically correct your tax return and add it back, but it may delay your refund.
If you already received your refund, and the rebate is not part of your refund per line 30 of form 1040 then you probably don't actually qualify for one reason or another
