No, you do not have to first subtract the amount for any state or local financing that you got - you can take 30% off the full amount you paid.
There was a section of the law, before the Stimulus Bill, that required you to first subtract financing from state or local programs. But, the Stimulus Bill specifically removed this language, effective January 1, 2009.
Here's the language that was deleted:
(9) Property financed by subsidized energy financing
For purposes of determining the amount of expenditures made by any individual with respect to any dwelling unit, there shall not be taken into account expenditures which are made from subsidized energy financing (as defined in section 48 (a)(4)(C)*).
*The term "subsidized energy financing" (in section 48 (a)(4)(C)) means financing provided under a Federal, State, or local program a principal purpose of which is to provide subsidized financing for projects designated to conserve or produce energy.