File Too Big...way To Parse Out Data And Write To Csv

I have a file with multiple tabs of data...lot's of data (each tab has 80,000+ lines and 23 columns...3 are formulas, the rest is imported data). I've brought Excel to it's knees (i.e. crashes). Yes, I'm using 2007.

What I'm trying to do is extract 6 cells of data from every 10th line and write it out to a CSV file with two more pieces of information (same for each line).

What I was doing was creating a separate worksheet for each one to be extracted, parsing out the data, and then copying that data to yet another workbook that was then saved as a CSV.

First, in retrospect, that was a waste of time. Second, the addition of the extra worksheets to do the parsing was crashing Excel due to the extreme size of the workbook.

What I'd like to do is use a macro to do all of this in one swell foop:

1) Prompt me for a file name (or I can put the desired name in a cell and read it from there if that simplifies the code)
2) Open a new text file with that name and ".csv" extension in the same folder as the original workbook
3) Write out the column headers: (Fix, Satellites, Lat, Lon, alt (ft), Date, utc_t, course)
4) Step through each row, looking at the text contents of column B (looks like 22:50:07.100)...if it ends in ".000" do the following:
4a) write "PPS,4," to the open text file
4b) write the cell contents from columns "V", "W", "J", "C", "B", and "L" to the text file in the exact format they appear in the text cell.

The output file should look like (very short example):

Fix,Satellites,Lat,Lon,alt (ft),Date,utc_t,course
PPS,4,30.543203,-86.323328,1419.04,2009/12/17,23:26:22.000,243.95
PPS,4,30.539272,-86.332765,1831.53,2009/12/17,23:26:34.000,242.61
PPS,4,30.535680,-86.340912,2281.16,2009/12/17,23:26:44.000,244.34