A780GM-A Ultra RAID 5

So I am building a media server using the A780GM-A Ultra. Ill be running a phenom II 920, blu-ray/hd-dvd rom, 1 500gb Barracuda 7200.12 for the OS (Windows 7 RC1) and want to create a 4x1.5TB RAID 5 array. A few questions I have:
1. Has anyone created a RAID 5 array using this board? Any feedback?
2. I am trying to keep costs contained, is this the way to go for a RAID 5? What about software?
3. There are only 5 SATA ports on board, and out of the gate I need 6, can anyone recommend the cheapest reliable way to add more ports?
4. What is the maximum number of drives I can put into this RAID array? Can I expand the array later on?

I know there are lots of questions, but this will be my first RAID array to ever create.

Thanks for any and all help.

Marco, yes that is the board I ordered, I keep getting confused, I guess that answers my question about the number of ports!

Since you're trying to contain costs, why not drop the CPU back a few notches? Unless you're going to be using this machine for [a lot of] other tasks, a 4850e is probably enough.