Total values from date range table

I don't know where to start with this one.

I need to put a Start and End date range in the bottom fields so it will total the values that fall within that date range.

PHP Code: 

    October    November    December
1    1.5    0.0    0.0
2    2.7    0.0    2.0
3    0.0    0.0    2.0
4    0.0    3.4    1.8
5    0.0    3.6    0.0
6    3.5    1.8    0.0
7    7.0    1.5    0.0
8    3.9    0.0    0.0
9    3.6    0.0    0.0
10    2.0    0.0    1.0
11    0.0    0.0    1.6
12    0.0    0.0    0.0
13    0.0    0.0    0.0
14    3.9    1.5    0.0
15    1.3    0.0    0.0
16    3.8    0.0    0.0
17    2.0    0.0    0.0
18    0.0    0.0    0.0
19    0.0    0.0    0.0
20    3.8    0.0    0.0
21    1.8    0.0    0.0
22    1.5    0.0    0.0
23    0.0    0.0    0.0
24    2.0    0.0    0.0
25    0.0    1.7    0.0
26    0.0    0.0    0.0
27    2.3    0.0    0.0
28    3.3    0.0    0.0
29    0.0    0.0    0.0
30    0.0    0.0    1.2
31    0.0        0.0
Total Hours    49.9    13.5    9.6
Start Date    1-Oct-08                 7-Nov-08    1-Dec-08
End Date     6-Nov-08     30-Nov-08    29-Dec-09
          Total Here            Total Here            Total Here 


As you can see with the Oct-Nov range, they can overlap months, so simply summing the column of the appropriate month won't work.

Sorry for the formatting of this post, not much time at work to submit properly.

Thanks for the help.