hmn, my guessm you dont have a dedicated gpu (hence its zero), and the other is the iGPU.
if this is correct, then you can increase the shared (the 358) thru the bios. but the other one, sorry but there's not much you can do. Almost all laptops cannot upgrade gpu's (or add one).
keep in mind that if you increase that memory, it will lessen the system memory in effect. if you are not gaming then i don't think there's reason to increase it unless you have other valid reasons.
and it won't be playing heavy games anyway, even if you give it 2gb of memory