The council shall have the power to levy, annually, taxes upon all taxable property within the city, in addition to other taxes, and in sufficient amount for the purpose of paying the interest and coupons as they become due on all bonds now issued and outstanding, and such taxes shall be collected in the same manner and time as other taxes. The mayor and council shall also have the power, by ordinance, to issue bonds, payable in one year, to an amount not exceeding half the current revenue for the fiscal year, and also to issue bonds in renewal of other bonds of the city maturing for the requisite amount, and which the city has no fund to pay; provided, however, that such renewal bonds shall not bear any greater rate of interest than did the original bonds, and shall not run for a longer time than ten years. The mayor and council shall also have power by ordinance to issue bonds for the purpose of funding the floating indebtedness of the city existing at the time of its incorporation as a city of the third class; provided, however, that such bonds shall not draw any greater rate of interest than six percent per annum, payable semiannually, and shall not run for a longer time than ten years.