Sum totals from beginning of last year to the end of last month last year

Today is June 11th, 2015. I have a area on my spreadsheet with the title ="YTD Sales to the End of "&$C$57 ,where C57 is dynamic and its always equals last month. So what is displayed is "YTD Sales to the End of May"

One of my columns is "LYTD Sales" in which I need excel to add up all the sales with a ship date between 1/1/2014 to 5/31/2014.

Here is the last part of the formula I'm using to add up all the sales with a ship date between 1/1/2015 to 5/31/2015(YTD Sales)
[Ship Date],"<="&EOMONTH(TODAY(),-1)

How do I edit this to equal "LYTD Sales to the End of May" and still keep it dynamic.

Figured it out.....that was easy

"<="&EOMONTH(TODAY(),-13)

Now if I can find out a way to add reputation to myself from myself for getting the answer.

You're Welcome