The Des Moines City Council will be asked today to spend up to $4.5 million in tax increment financing funds to help cover the estimated $45 million renovation of the former Younkers department store building at 713 Walnut St.. Under the proposal, the city would pay $675,000 a year for 10 years, with the payments offset by 85 percent of the commercial rents collected during the previous year. The payments would begin no sooner than July 1, 2012. The Alexander Co. of Madison, Wis., has proposed a historic restoration of the Younkers building that would include 69 market rate apartments and 73 apartments to be leased to households making up to 80 percent of the area’s median income. Retail space would be located on the street level of the entire building and the skywalk level on the east half of the block. The former Younkers Tea Room is included in the restoration.