I need help setting up a RAID system

Hi,

So I've had a NAS Server built for about 2 years now, all that it has in it at the moment is a 2TB data drive and a 20GB OS drive. But I want to take it to it's full potential now that my money situation is in check. I'm going to be buying 5 more 2TB HDD's and I want to RAID them together. My issue is that in all my years of working with computers, I've never once dealt with RAID before .

This machine is running Windows Server 2008 R2 on a Mini ITX motherboard in a Lain Li Server case, with 6 3.5" HDD bays.

Complete systems specs:
CPU: AMD Phenom x4 @ 2.2ghz
RAM: 4GB DDR2 @ 800mhz
EVERYTHING ELSE: Onboard

This is the exact motherboard that I have right now.

Newegg.com - ZOTAC GF6100-E-E AM3 (up to 65 watt TDP) / AM2+ / AM2 NVIDIA nForce 430 MCP Mini ITX AMD Motherboard

Now as you can see it only has 4 SATA ports. I need 8 in total, 1 for my 2.5" 20GB OS Drive, 6 for my 12TB of Data drives, and 1 for my Hot Swap bay. So what I was thinking is I could get this RAID card.

Newegg.com - SYBA SY-PEX40013 PCI Express SATA RAID Controller Card

Now what I'm trying to do exactly is RAID the 6 2TB HDD's together for a total storage of 12TB showing as 1 drive in Windows. I'm not concerned about performance because this is just streaming movies/shows to my WD TV Live that is sitting right next to the server, connect via gigabit network.

But because I've never worked with RAID before, I don't know how to go about using 2 different controllers as one, would I do that in BIO's or with software, which RAID version would be the best and simplest for me to use? Please give me any details to make my purchase/setup as easy and as painless as possible. The only thing I'm not willing to do is buy a new motherboard/server setup. I didn't buy the RAID card yet, so if you have any other suggestions, please link them to me :)

Thanks a lot in advanced :)

And just for a little more added info, this is the hard drive I have, and I will be buying 5 more of these

Newegg.com - Seagate Barracuda Green ST2000DL003 2TB 5900 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

Ok, that's what I was thinking about doing, but I just didn't know if that was a good idea. The issue I'm facing now is finding a card that has 6 SATA slots, or at least a 2 SAS slots that can be split to SATA, I want to stay around $100 and it has to be PCI-e 1x. It's not a server board, it's just a basic Mini ITX PC motherboard.

So if anyone knows of a PCI-e 1x RAID card with either 6 SATA II connectors or 2 SAS connectors that's has splitter cables with it.