I have 32 GB external, but my internal is only 4GB!
From my point of view, the best solution is to root Your phone and install Links2SD or App2SD ROOT PRO form Play Store. If rooting is not avaliable (lost of guarantee) please use App2SD for non-root users. There is a lot of such apps in Play Store. It moves parts of apps to SD card and frees space in internal memory.
But if You root Your device, all app parts can be moved to SD, even part of system apps.