Hello and Help!

I have a 3 workbooks with 6 worksheets in each. Each worksheet
contains about 20-25000 rows of information! These workbooks need to
be updated monthly. If you do the math, that's a lot to sort through
and update. It use to take almost a month to update everything for the
last month. I have been able to take it down to a little under 2
weeks. Here's a sample:

STYLE DESCRIPTION FEB MAR APR MAY JUN JUL TOTAL
XXXXXXXX
ABC123 SALES ACTUAL 0 0 0 0 0
SALES PROJ 0 0 0 0 0
SALES PROJ 0 0 0 0 0
SALES LY 0 0 0 0 0
Chg Act/LY 0 0 0 0 0
BOM ACTUAL 0 0 0 0 0
BOM LY 0 0 0 0 0
Chg Act/LY 0 0 0 0 0
PROJ REC DIV 0 0 0 0 0
PROJ REC FMG 0 0 0 0 0
DIFFERENCE 0 0 0 0 0
ORDERED 0 0 0 0 0
SHIPPED 0 0 0 0 0
% FILL 0 0 0 0 0
ORD/PROJ 0 0 0 0 0
VEND PROJ REC 0 0 0 0 0
VEND BOM ONH 0 0 0 0 0
VEND ACT REC 0 0 0 0 0
PROJ REC/ACT REC 0 0 0 0 0

Some of the information is calculated, the rest is entry off vlookups
of different pivot tables.

What I would like is a VBA that would allow me to copy the vlookup by
row in the correct column I need and then change those vlookups in to
value.
For example: if I need the VEND ACT REC for July, I would like to have
a box that would allow me to specify that for all rows that have VEND
ACT REC to copy and paste a particular forumula in the column of my
choosing. I guess I would need a box that would ask me what I am
looking for by row and column. I guess the next line in the box would
ask me what formula I would like to copy and paste into the rows. The
next box would ask me which column do I need to start the copy and
paste in (because the rows would be any that have VEND ACT REC or any
variable that I desire). I would like to have a box that I can check
off if I want to change the forumlas to values after done.

I also need the formula to correctly reference the correct cell in the
vlookup. If the vlookup in the example will be using $A3 as the value
to lookup, when the formulas are copied and pasted, the next cell to
reference in the example would be $A24 (consider a line skipped).

I hope someone can help me.
Thanks
Shawn