Swapping External Card and Internal Memory on Android?

Hey guys,i recently got GTA San Andreas on my Xperia J and the problem is that the game takes 2.6 GB of space and it must be installed on internal sd card/android/obb

Xperia J has only 2 gb of internal space and my external card has 16 gb.

Now,i've read about this stuff on the internet and it says that its possible to make ext card act like internal and vice versa but no one gave exact instructions on how to do it.

Do i need to root? Is it possible without root? How can i do it? Can i somehow install apps on ext card without swapping? Is it safe?

On google play it says San Andreas isn't compatible with my smartphone and gta 3 said that too but i got it on my device and it worked,so it ain't my device its space on internal.