Need new security appliance

[Stephenish]

I am looking for a cheap yet effective security appliance. I run a small farm of BOINC machines and I need a way to secure them from internet attacks. 5 computers, PS/3, a pair of switches, and a VOIP box. These devices should have constant access to the internet.

 

[Stephenish]

I am being broken into regularly, and need some way to stop the attacks.

I don't know what features are available for a reasonable price. No subscription would be nice, but if I have to, I have to.

 

[Stephenish]

I already have a router with security features, NAT & SPI I think. Standard router for U-verse service from AT&T.

 

[Stephenish]

Oh and also, I have a 12Mbps down and 1.5Mbps up. I want a security device that can process that.