Incremental Increase By Week When Total For Month Is Known

I have been a long time lurker of MrExcel, but have always been able to find the answer to my question within the forums. However, I am stumped. I am trying to create a pivot table that will show incremental goals by week, when I have a set goal for the month already. However, I don't want to do a straight average across all the weeks in a month. I would like to see it continually grow during the month. How can i mathmatically do that in Excel?

For example:

Jim had 191 sales leads in the last week of the month in December. Of those 191, he closed 29 of them, for a 15.2% close rate. I want to see him raise that by 6% by next December, so (6%/12 (# months) = .5%). He will need to increase his close rate to 15.7% by the end of January. So, for the month of January, we expect 955 sales leads (5*191) and 149.935 (15.7% of 955) closed. However, I don't want to say Week 1, 2, 3, 4, and 5 in January should all have 29.987 closes, I would like to be able to say week 1 = 25, week 2 = 27 week 3 = 30 week 4 = 32 and week 5 = 34, but have that incremental increase to total 149.935.

There is (sadly) no changing the percents, or the closed leads number. These have already been submitted and aproved. I just have to be able to let people see the goals by week now, but if they want to see the monthly goal, it must equal what has been approved.