Update Data selection for chart based off a referenced cell

hello,

I am using excel 2013 and I want my simple line chart to update the data used on the x-axis based off an absolute referenced cell. my data is set up like this below.

October-14
Week 2



Month July 14 August 14 September 14 October 14
Week 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4


Total Actual % 46% 48% 50% 50% 48% 48% 48% 48% 48% 48% 48% 48% 48% 48% 0% 0%
Total Proforma % 71% 71% 71% 71% 71% 79% 79% 79% 79% 81% 81% 81% 81% 81% 81% 81%

formatting of my information isn't displaying properly (newbie to the forum). each month has 4 columns associated with it and the 1,2,3,4 correspond to each week(column).

Pretty much I want the chart to update based off the week # and month of the upper left. I.e. for October and week 2, graph the data from 1st week of july until the 2nd week of October for both series of data. I am completely stuck with this one and can't figure it out. any help would be appreciated.

thank you!