I would like to thank you for contacting us and providing that interesting article related to RAM in 32-bit based OS.
The best way to go and get the full capacity from your system would be to change your OS to it's 64-bit version (clean installation would be required).
With that version you should not have issues while using more than 4 GBs of RAM.
I would like to recommend you to check this FAQ related to your inquiry, here you would find some additional information about how these versions (32/64-bit) work:
If you require any further information or support, feel free to contact us back.