That's a big csv file!
Is the data in the file structured like a traditional data table ie a single record in each row, discrete data in 'columns'? If so, you can use Data>Import Extrenal Data>New Database query (xl2003 and below, similar-ish steps in 2007) to query the file using SQL (and hence filter it).
If not, then you will need to explain how the data is structured and what you wish to extract (perhaps with an example of what the data looks like).