It is quite convenient to treat a csv file as a regular table where columns contain different data and each row belongs to a product.
First of all you should arrange your data by columns and determine what columns you need there. It can be done in a xls file (without using any color/text formatting). The file should have at least the model and product name columns. Here is an example of the simplest csv file importing 3 new products:
model,product name
mod1, test product 1
mod2, test product B
mod3, the third test product
I would suggest you take a sample file here:
http://www.ka-station.com/samples/csv/demo.xls
Delete all data from this file except the first line and put your data to rows similar to the demo data. Columns which you do not use can be removed from the file. Next, you will need to save this file as a CSV file and try to import it to the extension.
For editing xls/csv files I recommend to use a free OpenOffice Calc application which works better than MS Excel for these cases, but MS Excel (any version) is OK too.