splitting import of file material from wp.com to wp.org

I’m having trouble with the data importing from wordpress.com to www.ads-software.com. The Importer plug in seems to have some issues but apparently that is the only option. there seems to be a lack of access to data on this issue. My file is just under 11 MB .xml. I’ve been told to split the material up – how do I do so?

Thank you.