Converting internal android system (fat32) to ntfs topic

I want to download something from my work wifi. My connection is to slow at home. Anyways the file is over 5 gb. Frm what I read around is that android system doesn support files over 4gb.... I'm runing jellybean neatrom (rooted) Was wondering is there anyway to conver my system into ntfs so I can download this file? I have an external sd card but only 4gb. My internal has around 10 gb free and would like to use that..

Is there anything I can do?