I've forgot to inquire you about it, but what's the engine and transmission in your Altis? My grandma also has one, with the 1.8L flexfuel engine and the 6MT.
I assume shifting gears manually back there would be extremely discomfortable with all that stop-and-go, and wear out a clutch pack quite quickly. BTW have you already considered some engine mods to increase its efficiency, such as getting a Prius-like intake camshaft and a supercharger?