What To Use To Backup My Whs

I've looked around, read as much as I can, and am at my wits end. What do I need in order to backup my WHS?

The current config is:

230GB disk broken into a 60GB OS partition and the remainder used for file shares
1 TB disk used for file shares
2 TB disk used for file shares

in addition I have (4) external USB drives that are 2 TB each.

I want to plug two drives in (A set) and do a full backup on Sunday, then an incremental backup on Mon, Tue, Wed, Thu, Fri, Sat.
On Sunday I unplug the two disks (A set) and send them off site and plug in the other two (B set) and run a full back up on Sun, etc...
At the end of the week swap A and B sets again.

What software will let me do this? I'm pretty sure Backup exec would work but I don't have $1,000+ to drop on this. $100 or $200 sure. I already wasted time with HandyBackup, I tried CrashPlan but that doesn't seem to have any useful options either.
I want to backup the full system, OS and shares.
Unless that is totally unfeasible, in which case I'll settle for backing up the shares.

Is this backup plan bad for some reason? Is that why nothing seems to support it?

Thanks in advance.