Question Regarding Motherboard and Upgrading Memory

Hi,

I am looking to upgrade the RAM on my PC from 6gb to 16gb's.

My first question would be ... for someone that does use his computer a lot - for both gaming / multi-tasking and general purposes would upgrading from my existing 6gb's of RAM really be worth it ? My computer specs will be listed below FYI.

My second question is the following: I have an ASUS Motherboard (ASUS P7P55D-E LX - motherboard - ATX - LGA1156 Socket - P55 - LGA1156 Socket). Now I am not super computer savy but I do know a bit about computers. What is throwing me off is the kind of memory that I should get and whether that memory will properly work with my motherboard.

My current memory is 3 sticks of: http://www.centon.com/cmp/cmp1600pc204801

I would preferably like to purchase the ne new memory (if even needed) from amazon.com since I have a discount there.

I do have Windows 7 64bit and with all that I listed above I basically just want to see if:

A- There is a huge difference from my current 6gb's of RAM to 16gb's of RAM ?
B- Specifically what kind of memory do I need
C- Are there any worth while 16gb's RAM on amazon.com that would be worth it and fit into my machine.

Lastly, my final concern is if I were to get new RAM and pop it in ... do I have to do anything to the BIOS or OS or do I just pop in the memory into the slots and start my machine up as per usual.

-Thanks.