Hi Henrik, based on the Acer Aspire ES1-512 specifications I found online, your system includes Intel® Celeron N2840 Dual-core 2.16 GHz, which does not meet the recommended specifications to run Heroes of the Storm. This game requires an Intel® Core i5 processor with Intel® HD Graphics 3000 or better to run properly.
The graphics memory is allocated dynamically. Graphics Drivers — Graphics Memory FAQ for Windows 2000/XP/Vista/7*
I cannot tell if the driver from the page you linked above is appropriate for your system since it was uploaded by another user and not Acer*. However, you may try with the following driver for your operating system architecture: