Search column with multiple conditions

Encl file is self explanatory. Want help in formula entered in cell D15

Thanks in advance.

1.The column D is a 11 digit code that has to be allotted in chronological order everyday for each transaction. IT has three parts "IC/", three digit serial number and "MMYYY".
2. Now assuming that a new transaction has been done today viz. 18th Feb 2014, my job is look above in the column which has data from beginning of the year (say around 1500 rows) and find for the current month, what is the largest serial number i.e. the middle part. In the file, we have data for Feb 14 and the largest serial number is 12. So I want the formula should display the "IC/012/Feb14" in the file.

What I would do then is to use the formula SUBSTITUTE(D15,MID(D15,4,3),TEXT(VALUE(MID(D15,4,3))+1,"000")) to display it as "IC/013/Feb14". and it goes on. When the next month comes, it will search for March data, and if there is none, it would display "IC/000/Mar14" and after I use substitute, it will display "IC/001/Mar14".

Now I feel that I have explained enough. I am really sorry if I have communicated insufficiently. This help is badly needed. Thanks