Finding n-th largest value in a database, column given by another cell

I'm having a lot of trouble to get around this one!

A have a large database of sales by client, with each row for a different cliente and each column representing one month of the year in a "jan/13", "feb/13", ..., format.
I know how to identify the n-th lasgest value in each of the columns with the large function, but I want to make it easier to determine it each month, without having to add unnecessary stuff to my workbook, since I only need to have this info once a month and only for 1 month at a time, but for quite a number of different databases...

In a different sheet, I want to be able to input the month/year in a given cell (say A1), so that a table below automatically updates the top 10 clients for the input month/year, without having to change the column used in the large function's formula range.

I've done similar stuff to replace the vlookup function, using the match function to give me the column number I need, but in this case I don't see how I can input a column number into a function that works in a similar way to the large function.

Any help would be very appreciated!!

Thanks

Ok, so here goes a file where I try to demonstrate what I need!

Sample sales.xlsx

On the "Top" sheet, I would like the ranges C7:C16 and H7:H16 to update automatically when I change C2 to any other month of the year (november and december do not have any data yet).

So far, to change these ranges to any other month I have to manually replace the L column in the LARGE funcion to the reference column I want on the "Sales" sheet...

If you could give me any help it would be great =)

Thanks

I actually am struggling to understand the solution you came up with, I did not understand the way you tied the date to the columns, but anyways that posed me another problem... in several cases I don't want to LARGE function to go through all the lines in the table, just part of them...

So, I started to play around with other functions and reached a good solution which is maybe easier to understand and does not require any additional items. It combines an OFFSET function with a MATCH function to determine how many columns the offset reference should advance.

In the attached file you can see how it works =)

Thank you so much for your help, it helped me address the problem in a different way!

Sample sales.xlsx