HUGE blogger to WordPress import – how to?

What are the steps that can be taken to convert a HUGE Blogger export file (50 MB) from XML to WXR? Is there a way to break the Blogger XML down into smaller sections and convert them piecemeal? If yes, can you share with me how to do that or what the format should be?

I know that I can cut up a WXR file (by retaining the header and footer information and cutting out some of the post content) to make it smaller and upload-able. Would a similar approach work with converting the Blogger file to a WP format?

Any help would be much appreciated!