Lookup data from large CSV file

[gareths]

I'm basically trying to lookup data from a large csv (76Mb) where if the values in adjacent cells of the .xls (say A1 and B1) fall within the ranges of 'xcoord' and 'ycoord' (columns A and B) in the csv then a 'postcode' (column C) is returned from it that can be placed in the .xls

For example if the csv looks like this:

376895,379133,AAA123
376895,820494,AAA124

and the .xls like this:

A1________B1
376895____389155

then a value of AAA123 is returned in cell C1.

Is there a way to do this using vlookup or a macro?
Thanks!

 

[gareths]

I forgot to add the csv is called Data.csv in C:\temp and I'm using excel 2003.