Excel 2007 : Vlookup -New Excel 2007 User

[zitu708]

Hey i am a new Excel 2007 user.
I am using VLOOKUP function as follows-
VLOOKUP(A3,'History'!$B2:$E2000,2,FALSE)

Here I want to replace value "2" in "$B2" dynamically such that the new value which is available in a different cell can replace it. Suppose cell P22 has value 46, so dynamically my function becomes
VLOOKUP(A3,'History'!$B46:$E2000,2,FALSE)


Thanks.