Help selecting a raid controller/HDs

Hello,
I am looking at building a simple backup server on an old desktop. I am building this on a hp pavilion a747c with thehttp://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=us... specs of the MB here

I am looking at 1tb HDs in a raid 1 configuration.

Based on my understanding I would need a RAID controller but do not need a high end one (or do i). I also do not want to spend extra money on faster HDs that I am unable to utilize.

I would appreciate any help.
Thanks