copy the apk in a folder on your pc and extract it
go inside the folder /lib/armeabi/ and you find this file
libSwypeCore.so
copy this file on your leo sd card
boot up android and with rootexplorer cut/paste the library file inside the folder /system/lib
reboot
after this, swype should be in your inputmethod choices
If the copy of this file is not allowed (and the system show up a message like "read only filesystem" and such things), I think you have to do this operation with a terminal with root permission (inside android, on your pc with adb shell, on a linux pc, and so on)
Otherwise, the way that can't fail is:
on your pc (a linux pc would be better) mount the system file in a folder, do the cut/paste operation, umount the system file, reboot android
Hope this help (and hope you understood what I mean ... sorry for my english)
Regards