The Parking Authority shall have power to take all steps and proceedings and to make and enter all contracts or agreements necessary or incidental to the performance of its duties in the execution of its powers under this article and as provided by statute; provided, that any contract relating to the financing or the acquisition, construction, extension or improvements of off-street parking facilities or of any trust indenture relating thereto shall be approved by Council. (1969 Code Sec. 2-77)