Function that will return value of a cell based on a date in a third cell

I have been struggling with trying to get a range of cells to return a value from a call when the date matches in a second cell.  I have attached an example of what I have been struggling with.  Example:  I want a formula that would be placed in all of the cells in the range from D3 through R15 that would populate the value from column A into the corresponding date column based on the date contained in column B.  I tried using a nested IF function but could not get it to work.  Am I using the wrong function?  Is there another function that would be easier to use.  Searching the internet I have found no such solution.  Any help would be greatly appreciated.