Laptop Memory Question!

Here are my specs (my model number is HP ENVY Sleekbook 6-1129WM):
Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 8.1, 64 bit
Processor: AMD A8-4555M APU with Radeon(tm) HD Graphics, AMD64 Family 21 Model 16 Stepping 1
Processor Count: 4
RAM: 7642 Mb
Graphics Card: AMD Radeon HD 7600G, 512 Mb
Hard Drives: C: Total - 278472 MB, Free - 118602 MB; D: Total - 25632 MB, Free - 3013 MB;
Motherboard: Hewlett-Packard, 18DE
Antivirus: Windows Defender, Disabled
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Question:

I can't access my computer bios, But that is not my main concern.

My main one is the fact that I installed an additional 4GB RAM on top of the already installed 4GB (8GB Total) and now I would like to increase my laptops graphics memory to 2GB.

I have AMD Overdrive installed, but i'm not sure how to increase the graphcis memory from there.

I need a detailed explanation on how to increase graphics memory for AMD Overdrive.

Much appreciated!