Increase performance of csv

Hi,

I have csv file which contains 1 million records and with column 160. I have to insert(update the csv file) more 60 columns in the same file so the total column finally will generated 220.

60 columns and there data will get update like -
for first Row I have to select values from column 2,3,4 and generate the url and execute the url so that I will get xml data. Then I have to parse that data and fill 60 columns for that perticular row.
Like same I have to do for 2 row and 3row....upto 1 million. I have to process this file within 3 hrs.

How I can improve the performance of the reading and writing to csv file.


Regards,
sjs